Self Study Programme 643 For internal use only.7-speed dual clutch gearbox 0BZ – S tronic in Audi R8 (Type 42 and 4S)Audi Service Training BackWith the product upgrade of the Audi R8 for the model year 2013, the 086 R tronic automated 6-speed manual gearbox was replaced by the new 0BZ S tronic 7-speed dual clutch gearbox. Like the R tronic, the new R tronic is very much a sports gearbox. The fundamental advantage of the S tronic is that gear shifting takes place virtually without interrupting power transmission. That, in turn, lends the Audi R8 a high level of driver convenience. The 7 speeds make it possible to provide either a wide spread of ratios to reduce fuel consumption or a close-ratio configuration for better acceleration performance.Forwards Ξ ContentsThe S tronic offers agility and easy gear-shifting. The high customer expectations in terms of handling dynamics and driver convenience are thus equally satisfied. The 02E 6-speed dual clutch gearbox was the first design of this type at Audi. The basic functions of the dual clutch, gear-shift and electro-hydraulic control modules are described in detail Self-study Programme 386 and are thus not explained any further in this SSP. Therefore, if you require any information please refer back to SSP 386 and the succeeding SSPs on dual clutch gearboxes.643_002Learning objectives of this self study programme: This self study programme provides you with information about the 0BZ 7-speed dual clutch gearbox. After you have completed this self study programme you will be able to answer the following questions: • What is the design of the 0BZ 7-speed dual clutch gearbox? • How does the 0BZ 7-speed dual clutch gearbox function? • How does the 0BZ 7-speed dual clutch gearbox differ from the dual clutch gearboxes we are already familiar with? • What are the transmission-specific differences between the Type 42 and the Type 4S?2ContentsIntroductionOverview ______________________________________________________________________________________________________________________________________________________ 4Selector mechanismAudi R8 (Type 42) selector mechanism ____________________________________________________________________________________________________________________ 6 Audi R8 (Type 4S) selector mechanism ____________________________________________________________________________________________________________________ 8Gearbox functionsAuto-P function _ ____________________________________________________________________________________________________________________________________________ 16 Tip-shifting in D/S ___________________________________________________________________________________________________________________________________________ 16 Activating transmission setting N (holding P-OFF setting) _ ____________________________________________________________________________________________________________________________________ 16 Launch control program ____________________________________________________________________________________________________________________________________ 16 Special features on Type 4S ________________________________________________________________________________________________________________________________ 17 Audi drive select – gearbox setups ________________________________________________________________________________________________________________________ 18Gearbox assembliesSpecifications _ _______________________________________________________________________________________________________________________________________________ 20 Overview and features ______________________________________________________________________________________________________________________________________ 20 Differences on the 0BZ gearbox between the Type 4S and Type 42 ____________________________________________________________________________________ 23 Component overview _______________________________________________________________________________________________________________________________________ 24 Gearbox cross-section – gear set/gear train configuration _____________________________________________________________________________________________ 26 Dual clutch ___________________________________________________________________________________________________________________________________________________ 28 Gear train and gear set _____________________________________________________________________________________________________________________________________ 32 Gear shifting and gear-shift actuators ____________________________________________________________________________________________________________________ 34 Power transmission path in gearbox ______________________________________________________________________________________________________________________ 36 Parking lock – mechanical function _ ______________________________________________________________________________________________________________________ 40 Parking lock – electro-hydraulic function _________________________________________________________________________________________________________________ 42 Emergency release, parking lock __________________________________________________________________________________________________________________________ 46 Parking lock emergency release on Audi R8 (Type 42) __________________________________________________________________________________________________ 47 Parking lock emergency release on Audi R8 (Type 4S) __________________________________________________________________________________________________ 48 Oil system and ATF supply _ ________________________________________________________________________________________________________________________________ 50 Oil level in the gearbox _____________________________________________________________________________________________________________________________________ 52 Lubrication and cooling of the gear train _________________________________________________________________________________________________________________ 54 ATF temperature management ____________________________________________________________________________________________________________________________ 56Gearbox control unitComponent overview _______________________________________________________________________________________________________________________________________ 60 Mechatronic module ________________________________________________________________________________________________________________________________________ 62 Description of solenoid valves _____________________________________________________________________________________________________________________________ 66 Auxiliary hydraulic module _________________________________________________________________________________________________________________________________ 68 Parking lock module ________________________________________________________________________________________________________________________________________ 69 Gearbox control units _______________________________________________________________________________________________________________________________________ 71 Sensors and information ___________________________________________________________________________________________________________________________________ 72 Function diagram ___________________________________________________________________________________________________________________________________________ 78 Hydraulic circuit diagram _ __________________________________________________________________________________________________________________________________ 80AppendixTest your knowledge ________________________________________________________________________________________________________________________________________ 82The self study programme (SSP) teaches a basic understanding of the design and mode of operation of new models, new automotive components or new technologies. It is not a repair manual! Figures are given for explanatory purposes only and refer to the data valid at the time of preparation of the SSP. This content is not updated. For further information about maintenance and repair work, always refer to the current technical literature.NoteReference3 BackForwards Ξ ContentsIntroductionOverviewThe 0BZ S tronic 7-speed dual clutch gearbox was first introduced on the Audi R8 Type 42 for the MY 2013 product upgrade. The quattro drive concept was carried over unchanged. Power transmission to the front wheels is by way of the 0AZ front final drive with viscous coupling as before. The differential lock in the rear final drive has been taken over from the 086 differential. See SSP 613 – Audi R8 power transmission. On the Audi R8 (Type 4S), the 0BZ S tronic 7-speed dual clutch gearbox is fitted as standard with all engine variants. The power transmission to the front wheels on the Audi R8 (Type 4S) is via the new 0D4 front final drive with electro-hydraulic multi-plate clutch. See SSPs 641 and 642. The design of the differential lock in the rear final drive has also been carried over but with adapted locking characteristics to suit the redesigned power distribution to the front wheels. The drive response and handling dynamics can be varied to suit the driver's preference using Audio drive select and a choice of gearbox programmes. See page 18.Automatic gearbox control unit 2 J1006 • Installation location in Audi R8 (Type 4S): in engine bay, on left-hand side4 BackForwards Ξ ContentsSelector mechanism • Audi R8 (type 42)0D4 front final drive with electro-hydraulically controlled multi-plate clutch on Audi R8 (Type 4S). See SSPs 641 and 642.Control unit for all-wheel drive J492 • Audi R8 (type 4S)Selector mechanism • Audi R8 (type 4S) Parking lock emergency release mechanism • Audi R8 (type 4S)Automatic gearbox control unit 2 J1006 • Installation location in Audi R8 (Type 42): behind right-hand seatOn the Audi R8 (Type 42), power transmission to the front wheels is by way of the 0AZ front final drive. See SSP 613 – Audi R8 power transmission.643_003 5 BackForwards Ξ ContentsSelector mechanism|The Audi R8 with the 0BZ S tronic 7-speed dual clutch gearbox has a selector mechanism and operation concept using 100% shift-bywire technology that is distinguished by the following features and functions: • There is no mechanical connection between the selector lever and the gearbox. • The driver input is registered by the selector mechanism and transmitted electronically to the gearbox without the need for a mechanical fall-back level. • The parking lock is actuated electro-hydraulically and activated automatically (Auto P function). • A mechanical emergency release enables the parking lock to be released if necessary. The 0BZ gearboxes on the Audi R8 (Type 42) and on the Type 4S are largely identical. However, the selector mechanism, the operation concept and the parking lock emergency release differ fundamentally in some respects. The Audi R8 (Type 42) uses the R tronic selector mechanism unchanged. See SSP 613. The operation concept has been suitably adapted to the 0BZ gearbox. The Audi R8 (Type 4S) has the same selector mechanism as is currently used on the Audi Q7 (Type 4M) and the Audi A4 (Type 8W). The operation concept has been adapted to suit the Audi R8 and differs only slightly from that on the Audi Q7 or Audi A4.Audi R8 (Type 42) selector mechanismThe selector lever positions and shift commands are registered by the selector lever sensor control unit J587, analysed and sent via the drivetrain CAN data bus to the gearbox control unit J217. The gearbox control unit selects the desired transmission setting and sends back the information about the selected transmission setting to control unit J587. In response, control unit J587 operates the LEDs of the transmission setting indicator Y5.Selector lever position display Y5 Sport mode button E541Sport mode button E541Pressing the "Sport" button in Automatic mode switches the gearbox to sport mode. In sport mode, the gear changes take place at higher engine speeds, the gear shifts are faster and the engine's response to the accelerator pedal is more progressive. As a result, the engine's power development is fully utilised. In tiptronic mode pressing the "Sport" button activates M sport mode. When M sport mode is active, the gearbox does not automatically change up when the up-shift threshold speed is reached. In normal tiptronic mode, the gearbox changes up when the up-shift threshold speed is reached,Bottom end of selector lever Hall-effect sensors643_004Selector lever position detectionThe selector lever positions are monitored by multiple Hall sensors. At the bottom end of the selector lever there is a permanent magnet which controls the corresponding sensors according to the selector lever position. The selector lever sensor module J587 analyses the signals and communicates the selector lever positions to gearbox control unit 1 J743. From that information, J743 identifies the driver's wishes and operates the corresponding gear selection and clutch functions.Selector lever sensor control unit J587 with selector lever position sensorsPermanent magnet; a rubber ring at the bottom end of the selector lever deadens the impact noises.643_0056 BackSelector lever in left-hand normal position Selector lever in right-hand normal positionForwards Ξ ContentsOperationBasic operation of the gears is explained in SSP 613 and in the Owner's Manual. The special feature of the Type 42 with 0BZ gearbox is that the parking lock cannot be selected manually. There is neither a selector lever position nor a switch for engaging the parking lock (position P). The parking lock is operated exclusively by the Auto-P function. See page 16. If work needs to be carried out on the vehicle with the engine running (in which case the parking lock must be engaged), the parking lock can be engaged as follows: • With the engine running and the selector lever set to D, S, R, N or M, open the driver's door. or • Switch off the engine and then start it again. As long as a transmission setting is not selected, the parking lock remains engaged.Selector lever sensors control unit J587The selected transmission setting and the gear engaged are indicated on the instrument cluster. In the situation described above, make sure that the parking lock is shown as engaged (display shows P).643_006Selection of Automatic modeEngage forward gear or change up (tiptronic mode)Selection of neutral positionChange down (tiptronic mode)Selection of neutral position643_007Selection of reverse gear Selector lever in right-hand normal position643_008Selector lever in left-hand normal positionSport mode button E541Pressing the "Sport" button (E541) switches the gearbox to sport mode. The signal from E451 is read by the selector lever sensor control unit J587. J587 forwards the message "Sport mode" via CAN data bus to gearbox control unit 1 J743 and the engine control unit J623. Key: E541 Sport program button J587 Selector lever sensors control unit J743 Dual clutch gearbox mechatronic unit (gearbox control unit 1) Y5 Selector lever position display643_0097 BackForwards Ξ ContentsAudi R8 (Type 4S) selector mechanismThe Audi R8 (Type 4S) uses the latest-generation Audi B and C series selector mechanism with full "shift-by-wire" functionality. The operating concept is highly intuitive and is essentially identical to the familiar operating logic of automatic gearbox models. The parking lock is normally engaged and disengaged by the Auto-P function but can also be engaged by the driver using the P button. See page 16. After every operation, the selector lever always returns to the normal position of the automatic or tiptronic gate.Basic shift schematic Possible positions of the selector lever. The following indications are displayed in the self-diagnosis sequence according to the selector lever position: X - Normal position in automatic mode T - Normal position in tiptronic mode A1, A2, B1, B2, T+, and T- are the position indications in the selector lever position shown in each casetiptronic gate Automatic gate643_010Shift schematic Positions selectable without moving the selector Selectable drive positions Normal position of the selector lever and current drive position Software lock: cancelled by pressing the release button – E681 Software lock: deactivate by pressing the foot brake1) Mechanical lock by selector lever lock solenoid N110 – cancelled by pressing the release button – E681643_011Note: An acknowledgement tone sounds when drive position R is engaged.Automatic gateA2 A1 X B1tiptronic gateX B2 T+T T-643_013Speed-dependent gearbox protection function A change in driving direction from D to R and vice versa is only possible at speeds 8 kph. At vehicle speeds upwards of 8 kph, a gearbox safety function prevents the change of direction (power transmission to the other subset of the gear train).643_0121) he orange-coloured software lock is activated in drive position N after about one second. This allows quick-changing of the drive position T from D to R and vice versa without applying the brake. The makes it possible, for example, to free a stuck vehicle can be freed by rocking it backwards and forwards and makes it easier to shift driving position when manoeuvring.8 BackComponent overviewForwards Ξ ContentsHandle for selector lever top sectionSelector lever release button E681 – Release button Parking lock button E816 – P button – with parking lock indicator light  K320Handle for selector lever bottom section with selector lever gaiterSelector lever position display Y5Selector mechanism coverPlug connection E Selector leverPlug connection C Plug connection A Selector mechanism (selector lever E313)643_014Selector lever release button E681 – release button Button E681 is used for releasing the selector lever lock. It consists of two shift elements for reliability and diagnostics. In the event of a fault, release button E681 is considered actuated. The locks marked red and blue (Fig. 643_011) are disabled and fault is registered in the event memory and indicated on the instrument cluster. The selector can be moved out of positions P and N by pressing the foot brake.Parking lock button E816 – P button The P button is for manually deactivating the parking lock. The parking lock can only be activated at vehicle speeds 1 kph. Button E816 comprises three shift elements for reliability and diagnostics. Its shift status is transferred to the selector lever sensors control unit J587 via two interfaces. In the event of a fault in E816, a message appears in the instrument cluster and the parking lock can only engaged by the Auto-P function.9 BackForwards Ξ ContentsSelector lever sensor control unit – J587The selector lever sensor control unit J587 forms a functional unit with the selector lever position sensor G727 and the selector lever transverse lock sensor G868. J587 is responsible for detecting the driver input, analysing the button signals,communication with gearbox control unit 1 J743, and all selector mechanism control and diagnosis functions. J587 has the diagnosis address 81. The selector lever sensor module J587 registers the positions of the selector lever as shown in Figure 643_010 (A2, A1, X, B1, B2, T+, T and T-) and the signals from the buttons E681 and E816, and passes them on to gearbox control unit 1 – J743 via the drivetrain CAN. From that information, gearbox control unit 1 – J743 determines the desired transmission setting and initiates the appropriate functional operations (e.g. disengage parking lock, set gear train subset 1 or 2 to standby). J743 reports back the current transmission setting to the selector lever sensor module, whereupon it in turn operates the solenoid N110, the LEDs for the transmission setting indicator Y5 and the parking lock button K320. When a transmission setting is selected, that flow of information causes a brief delay before the relevant transmission setting symbol lights up.643_015Schematic diagram of selector mechanismSelector lever sensors control unit J587 Diagnostic address 81Selector mechanismSelector lever643_016VAS 642 001 The Y adaptor VAS 642 001 allows measurements to be taken between the selector mechanism (selector lever E313) and the transmission setting indicator Y5.CAN-High CAN-Lowinformation If there is a system fault on the selector mechanism, the transmission settings D and N can be selected by simultaneously pressing the two tiptronic paddles when the vehicle is stationary and the brake applied. See page 17.10 BackForwards Ξ ContentsSelector lever position sensor – G727The selector lever sensor control unit J587 determines all selector lever positions by means of the selector lever sensor G727. G727 consists of 2 sensors – one sensor for the automatic gate and one sensor for the tiptronic gate.How selector lever positions are detected: The longitudinal and transverse movements of the selector lever are transmitted to a slider with two diamond-shaped sender elements. The sender elements affect the magnetic flux in the sensor elements of G727 according to the movement of the selector lever. From the sensor signals, the selector lever sensor control unit J587 generates the following selector lever positions: • Automatic gate A2 – A1 – X (Normal position) – B1 – B2 • tiptronic gate T+ – T (Normal position) – TFor more details, see also the shift schematic on page 8.Selector lever in automatic gateB1 B2 X A1 A2Slider with sender elements for automatic and tiptronic gatesCircuit board containing selector lever sensor control unit J587 and sensors G868 and G727Plug connection ASelector lever transverse lock sensor G868 G727 sensor element for automatic gate Magnet for G868 G727 sensor element for tiptronic gate643_017Basic positionSelector lever in tiptronic gateTRestriction of the selector lever movement to one position forwards (T+) and one position backwards (T-) is achieved by means of the tiptronic gate track of the position engagement mechanism.T-T+Movement of the base plate together with the slider and sender elementsKey to schematic diagram of selector mechanism on page 10 E313 selector lever E681 Selector lever release button E816 Parking lock button G727 Selector lever position sensor G868 Selector lever transverse position sensor J587 Selector lever sensors control unit K320 Parking lock indicator light N110 Selector lever lock solenoid V577 Selector lever transverse lock motor Y5 Transmission setting indicator643_018 11 BackForwards Ξ ContentsSelector lever longitudinal lockSo that it is not possible to unintentionally shift the selector forwards in transmission setting D/S the selector lever is locked against forward movement. In transmission setting D/S, the selector lever lock solenoid N110 is energised and the locking pin engages with the selector lever lock guide. The selector can now be moved back into position B1 from the normal position in order to shift from D to S or from S to D. When the release button E681 is pressed, the power supply to N110 is disconnected and the lock is disengaged. To prevent unnecessary switching noises from N110, it remains energised when switching to the tiptronic gate. The lock against forward movement (A1) is inactive in the tiptronic gate, however, because the lock guide is tilted to the side and thereby rendered ineffective.Release button, selector lever release button E681PawlLocking pinSelector lever solenoid N110 • Energised in transmission setting D and S.Cross-piece with locking grooveB2Automatic gate of position engagement mechanism • The position engagement mechanism has 2 gate tracks, one track for the automatic gate and one track for the tiptronic gate.B1XA1A2Basic position12643_019 BackForwards Ξ ContentsSelector lever transverse lockTo ensure that the selector lever cannot be inadvertently moved into the tiptronic gate, it is transversely locked in transmission settings P, R and N.Selector lever transverse lock sensor G868 G868 uses Hall-effect sensors and a sensor magnet that is located at the end of the roller. The sensor magnet affects the signal of G868 according to the rotational position of the roller. From that information the selector lever sensor control unit J587 determines the position of the roller and thus the status of the selector lever transverse lock.Selector lever transverse lock active The selector lever is held in the so-called cross-piece. When the transverse lock is active, the locking cam is positioned so that it engages in the locking groove of the cross-piece. When the locking cam is in that position, the selector lever cannot be moved into the tiptronic gate.Transmission setting P/R/N – selector lever transverse lock activeSelector lever transverse lock motor V577Worm gearReciprocating plateRoller with swash plate, locking cam and sensor magnetSelector lever transverse lock sensor G868Magnet for selector lever transverse lock sensor G868Cross-piece with locking grooveLocking cam643_020 13 BackSelector lever transverse lock inactive To be able to change to the tiptronic gate from transmission setting D or S, the selector lever transverse lock has to be deactivated.Forwards Ξ ContentsSelector lever transverse lock cancelling function1The selector lever transverse lock motor V577 is operated by the selector lever sensor control unit J587 until the locking cam is disengaged from the locking groove of the crosspiece. The cross-piece is then no longer locked and the selector lever can be shifted into the tiptronic gate.2Transmission setting D/S – selector lever transverse lock inactive1V577Selector lever transverse lock sensor G868643_0212Locking camRoller with worm gearLocking groove clear – the cross-piece and, therefore, the selector lever can move sideways in the direction of the arrow – the illustration shows the position of the selector lever in the automatic gate.643_022From the position of the magnet, the selector lever sensor module detects with the aid of the sensor G868 that the selector lever transverse lock is not active.14 BackSelector lever transverse lock active In transmission settings P, R and N the selector lever transverse lock is activated to prevent the selector lever unintentionally being shifted into the tiptronic gate.. To do so, the selector lever transverse lock motor V577 is operated by the control unit J587 until the locking cam is engaged in the locking groove of the cross-piece. From the position of the magnet, the control unit J587 detects with the aid of the sensor G868 that the selector lever transverse lock is active.Selector lever transverse lock motor V577Forwards Ξ ContentsAutomatic resetting of the selector lever If the selector lever is in the tiptronic gate when the engine is switched off, it is automatically moved back into the automatic gate. The control unit J587 determines whether the selector lever is in the tiptronic gate or the automatic gate with the aid of the selector lever position sensor G727.Locking cam in position • "transverse lock active" Locking cam in position • "transverse lock inactive"643_023Magnet for selector lever transverse lock sensor G868Resetting function Starting from the position "transverse lock inactive", the motor V577 rotates the roller roughly ¾ of a turn in the direction indicated by the arrow until the position "transverse lock active" is reached. In the course of that rotational movement, the swash plate induces an axial movement (arrow) on the part of the crosspiece, thereby returning the selector lever to the automatic gate.Reciprocating plateLocking cam in position • "transverse lock inactive"The cross-piece (and, therefore the selector lever) is pushed in the direction of the arrow by the rotation of the swash plate. At the same time, the locking cam moves into the locking groove and locks the crosspiece. Consequently, movement of the selector lever into the tiptronic gate is barred.Resetting the selector lever in emergency mode If the tiptronic function cannot be performed due to a fault, the selector lever is automatically returned to the automatic gate and locked.643_024 15 BackForwards Ξ ContentsGearbox functionsAuto-P functionIn the case of the 0BZ gearbox, the parking lock is operated electro-hydraulically. See page 42. This allows the gearbox control unit to automatically operate the parking lock, thereby enhancing operating comfort. The Auto-P function engages the parking lock automatically (P-ON position) if the following conditions are satisfied: • Vehicle is stationary – vehicle speed 1 kph. • One of the transmission settings D, S, R or M is active. • The engine is switched off – Terminal 15 is off. For the Audi R8 (Type 42), the following applies: If the driver's door is opened when the engine is running and the seatbelt is not engaged in the belt buckle (seat belt not fastened), the parking lock is automatically engaged. On the Audi R8 (Type 42) the parking lock is engaged exclusively by the Auto-P function. If work needs to be carried out on the vehicle with the engine running, the parking lock can be engaged as follows: • With the engine running and transmission setting D, S, R or M selected, open the driver's door (seatbelt not fastened). or • Switch off the engine and then start it again. As long as a transmission setting is not selected, the parking lock remains engaged. The selected operating mode (transmission setting) and the gear engaged are indicated on the instrument cluster. In the situation described above, make sure that the parking lock is shown as engaged (display shows P). (holding P-OFF setting)Activating transmission setting NTo be able to move the vehicle without the parking lock for a limited amount of time, e.g. in a car wash, automatic engagement of the parking lock can be prevented. A condition for this is that the selector mechanism, the P button and the gearbox are working properly. To activate P-OFF, transmission setting N must be selected while the engine is running and then the engine switched off1). When the ignition is turned off, engagement of the parking lock is suppressed for a period of 20 minutes. After 19 minutes the following message is displayed in the instrument cluster: "Start engine to remain in N.“" along with a warning tone. If this instruction is not followed, the parking lock engages after 20 minutes and the system shuts down. If a speed signal (v  1 kph) is detected during this time, the period is extended according to the driving time of the vehicle until the system detects that the vehicle has been stationary for at least 5 minutes. While the vehicle is stationary with the transmission in P-OFF, power is consumed by the activity of the control units, bus network operation and the holding solenoid. If the vehicle is stationary for an extended period of time, the battery may become discharged to the extent that the parking lock automatically engages. Therefore, if it is necessary to keep the transmission in P-OFF for an extended period, the parking lock emergency release should be actuated. More information on "Holding transmission setting P-OFF" can be found on page 41.1)For the Audi R8 (Type 4S), the following applies: On the Audi R8 (Type 4S), the parking lock can also be engaged by the driver by pressing the P button, provided that the vehicle speed is 1 kph. The parking lock is disengaged automatically (P-OFF position) if the engine is running and one of the transmission settings D, S, R, N or M is selected. n the Type 42 the ignition key must remain in the ignition lock O in order to retain the P-OFF setting. Removing the ignition key causes the parking lock to be automatically engaged. On the Type 4S (100% keyless) the vehicle cannot be locked while P-OFF is active.Launch control programThe Launch Control Program regulates the maximum acceleration of the vehicle from a standing start. Please refer to the Owner's Manual for instructions on how to use it and follow the guidance provided. The Launch Control Program in the Audi R8 (type 4S) has a particularly sporty setup. In addition, forced up-shifts are performed in tiptronic mode. Refer to page 18. NotesTip-shifting in D/SManual gear shifts can be executed at any time using the shift paddles on the steering wheel (steering wheel tiptronic controls) in transmission setting D/S. Once the steering wheel tiptronic controls have been used, the transmission remains permanently in manual mode (tiptronic mode). There are 2 possible ways of returning to automatic mode: • Pull the selector lever back one position (position B1). • Move the selector lever into the tiptronic gate and back into the automatic gate.When pulling away with Launch Control active, all vehicle components are heavily stressed. As a result, greater wear may occur. The number of Launch Control starts performed is shown by the self-diagnosis reading Number_Launch_Control_Starts.16 BackForwards Ξ ContentsSpecial features on Type 4SSteering wheel tiptronicThe following functions can be selected using the shift paddles on the steering wheel (tiptronic steering wheel) on the Audi R8 (Type 4S): • If both shift paddles are operated simultaneously while the engine is running, driving position N is selected (while travelling and when the vehicle is stationary). • When the vehicle is stationary, the driver can shift from the transmission settings P, R and N to M1 by operating the Tip+ shift paddle with the brake applied. • Press-and-hold function: if the driver presses and holds the Tip+ shift paddle while the vehicle is moving, the transmission changes up to the highest possible gear, e.g. from 3rd to 5th gear. If the driver presses and holds the Tip– shift paddle, the transmission changes down to the lowest possible gear, e.g. from 7th to 3rd gear. • If a system malfunction has occurred in the selector mechanism, the driver can select driving position D with the Tip+ shift paddle when the vehicle is stationary and with the brake pressed. N can be selected by actuating both shift paddles simultaneously. R (reverse gear) is not available. These additional functions of the tiptronic shift paddles are made possible by the use of redundant backup systems for communicating the shift commands from the shift paddles The shift commands643_025are sent via CAN data bus to gearbox control unit 1 – J743 and also by 2 separate signal lines to the gearbox control unit 2 – J1006. See also schematic diagram on page 78. The information is then, in turn, sent on by CAN data bus to J743.Tip -Tip +Coasting mode1)If the applicable conditions are met, the gearbox can activate the coasting mode. The coasting mode is activated by opening the clutch which is currently engaged. In this way, the engine is disengaged from the gearbox. The vehicle does not enter overrun mode as it usually does, but rather rolls without any engine braking Activating the coasting mode The following prerequisites must be met before the coasting function can be activated: • • • • • • • • Audi drive select mode comfort or auto. Transmission setting D2) selected. Vehicle speed between 55 and 230 kph. Low negative accelerator gradient up to 0 % accelerator angle (driver takes foot off accelerator very slowly)3) Flat road or very shallow downhill/uphill gradient Cruise control not active. Selective cylinder shut-down not active. Refer to SSP 641, page 36. Start-stop system is not manually deactivated. effect and utilises the kinetic energy of its motion. Fuel can be saved by adopting an anticipatory driving style. The all-wheel drive clutch in the front differential is also disengaged in coasting mode.Deactivating the coasting mode Coasting mode is deactivated if one of the following controls is operated: • The accelerator pedal • The brake pedal • The Tip– shift paddle Coasting mode is also cancelled if one of the operating conditions listed above ceases to be satisfied.Notes on operation • In certain driving situations, coasting mode can be activated manually in the highest possible gear by operating the Tip+ shift paddle. • If coasting mode is deactivated by briefly applying the brake, it can be reactivated by pressing the Tip+ shift paddle again. • The Tip– and Tip+ shift paddles can be used to shift at random between overrun mode and coasting mode within the above parameters. oasting mode is not available on national variants due to marC ket-specific vehicle configurations. 2) In tiptronic mode, coasting mode can be activated in the highest  possible gear using the Tip+ shift paddle. 3) With a normal or high negative accelerator gradient to an accel erator position of 0% (driver takes foot off accelerator normally or quickly), the vehicle goes into overrun mode.1)17 BackForwards Ξ ContentsAudi drive select – gearbox setupsThe Audi R8 (Type 4S) is equipped with Audi drive select. That means that, depending on the vehicle equipment, the driver can experience the performance capabilities and dynamic handling characteristics of different vehicle systems. In addition to the familiar Audi drive select modes – comfort, auto, dynamic and individual – the Audi R8 (Type 4S) has a performance mode. Within performance mode itself there are 3 sub-modes – snow, wet and dry. Those setups allow the handling systems to be better adapted to the road surface conditions, i.e. the friction between the tyres and the road surface. The Audi drive select handling system utilises the electronic stability control (ESC) system in performance mode. Basic information about Audi drive select on the Audi R8 (TYpe 4S) can be found in SSP 641 starting on page 112. This section explains how the transmission control system reacts to the various Audi drive select modes.The comfort, auto and dynamic modescomfort and auto modes are identical as regards the gearbox setup. The shift points and the gear shifts are comfort-orientated. In dynamic mode the sport program S is selected in the gearbox. In the sport program the shift points are at higher engine speeds and shift times are reduced. This makes for better power delivery and more noticeable gear shifts. The overview on page 19 shows the effects of the various Audi drive select modes on the gearbox setup.snowwetdrylast mode Performancelast mode drive selectcomfortautodynamicindividualKey: Performance button Performance button adjusting ring643_026Audi drive select button/MMI turn-and-press knob Terminal 15 changeoverPerformance mode Performance mode is standard on the V10 plus and optional on the V10. In performance mode, the gearbox setup is super sporty. That means that the gearbox works to maximise power delivery from the engine; comfort plays a secondary role. Gear shifts are performed at very high engine speeds, gear changes are very fast and distinctly perceptible. Performance mode can only be activated and operated using the Performance button the steering wheel. The Performance button allows the driver to activate or deactivate performance mode directly and in any Audi drive select mode.information The following applies to vehicles for the North America region and all other countries from model year '17 on: If performance mode is selected, gearbox control unit 1 switches to tiptronic mode MS+ and automatic mode is not available.Please note that the stabilisation functions of the ESC and traction control systems are limited when performance mode is activated. You should only activate performance mode if you have the necessary driving skills and the traffic conditions permit. Danger of skidding!18 BackPerformance button The Performance button is a touch switch with an adjusting ring. The adjusting ring is used to select the snow, wet and dry modes. Those modes have no effect on the setup of the gearbox, however.Forwards Ξ ContentsAudi drive select buttonPerformance button with adjusting ring for selecting the snow, wet and dry modes643_027Overview of gearbox setups available with Audi drive selectAudi drive select modes Gearbox setups and functionsDriving position1) Shift characteristics Automatic upshifting in M mode Downshift during‑kickdown in M mode Modified accelerator map, increased idling and driveaway speed Launch control program No D normal – – comfort auto dynamic = sport program Performance No distinction is made between dry, wet and snow MS+ – No NoM – Yes YesD normal – –M – Yes YesS sporty – –MS – No Nonormal Nosportysuper sportyYes – with forced up-shift to M and with the most high-performance shift sequence and fastest gear changes Yes C – B No C – Yes D –Blipping the throttle during downshift Shift sequence/shift time Return to automatic mode after actuating the tiptronic shift paddles Engine start/stop mode Coasting mode2) Cylinder on demand4)No A NoYes C –No A NoYes Yes3) YesNo No NoKey to shift sequences/shift times: A B C D Comfort-orientated overlapping gear shift with engine torque intervention5) Shift-time-orientated overlapping gear shift with maximum engine torque intervention Fast overlapping gear shift with maximum engine torque intervention – specially adapted for tiptronic operation Fastest possible overlapping gear shift with maximum engine torque intervention and utilisation of engine inertial torque during upshifts he transmission setting is determined by the selector lever setting (D, S, or M) in combination with the choice of Audi drive select mode. T M means: tiptronic Manual shift program, MS means: tiptronic Manual Sport shift program , MS+ means: Manual Sport Plus shift program. 2) The operating conditions for the coasting function can be found on page 17. If selective cylinder shut-down is active, the coasting function  is blocked. 3) In tiptronic mode (M) the coasting function can be activated by means of the Tip+ shift paddle.  4) The operating conditions for selective cylinder shut-down can be found in SSP 641 on page 36. If selective cylinder shut-down is active,  the coasting function is blocked. 5) More information about "overlapping gear shifting with engine torque intervention" can be found in Self-Study Programmes 283 and 386. 1)19 BackForwards Ξ ContentsGearbox assembliesSpecificationsDesignations Manufacturer Service Sales DL800-7A 7-speed dual clutch gearbox 0BZ S tronicDevelopment/production Gearbox typeAudi AG Ingolstadt/VW plant Kassel Full synchromesh 3-shaft sliding-collar variable-speed gearbox with 7 forward gears and one reverse gear, electro-hydraulically operated gearbox for mid-engine concept, with differential lock in the rear final drive and PTO shaft for direct power transmission to the front final drive Two wet-type multi-plate clutches in an in-line configuration, electro-hydraulically operated and oil-cooled Mechatronic unit plus 2 additional electro-hydraulic modules (parking lock module and auxiliary hydraulics module) – shift-by-wire actuation with electro-hydraulically operated parking lock (park by wire), 2-control-unit concept for park-by-wire technology and separate clutch cooling for clutches K1 and K2. Automatic mode with various shift programs and tiptronic program for manual gear-shifting. • 6+E configuration on the V10 developing 397 kW (the 7th gear is a high ratio designed for fuel economy) • 7 speed configuration on V10 plus developing 449 kW 141 kg including ATF and dual-mass flywheelDual clutch Control systemRatio configurationWeightOverview and featuresThe illustrations show the 0BZ gearbox in the Audi R8 (Type 42).Parking lock emergency release mechanismGearbox ventParking lock module Connections for auxiliary ATF cooler with thermostat for oil temperature regulation – Only on Type 42ATF coolerGearbox nameplate Part number/serial numberATF pressure filter with heat shield20643_034 BackGearbox code/date of manufacture Electrical connection of parking lock module T16a Shaft for parking lock emergency releaseForwards Ξ ContentsElectrical connection of mechatronic unit T16cATF coolerMechatronic module J743 Gearbox vent Electrical connection of auxiliary hydraulic module T16bFront final drive input shaft The input shaft is also referred to as the PTO shaft. PTO stands for "power take-off".Dog – gearbox input shaft – Connection to engine via dualmass flywheelStarter643_035GearcaseThe gearbox housing essentially consists of 3 aluminium sections in which nearly all the oil channels are integrated. The cover for the clutch, the final drive and the mechatronic unit is also made of aluminium. The cover for the parking lock and the oil pan with integrated suction filter are made of high-grade polymer.21 BackThe illustration shows the 0BZ gearbox in the Audi R8 (Type 42).Forwards Ξ Contents597 mmA CAxial alignment of gearbox input shaftXB643_037A B Electrical connection of parking lock module T16a Electrical connection of auxiliary hydraulic module T16bC X Electrical connector T16c for mechatronic unit J743 Installation space requirement from axis of gearbox input shaft (= crankshaft axis) to bottom of gearboxThe 0BZ gearbox was developed specially for the new MSS platform1). That platform requires a gearbox with a short installed length. It also demands compact installation space requirements in order to be within the baseline limit X. Those requirements were essentially achieved by means of the following design features: • • • • Compact dual clutch with directly adjacent clutches Positioning of mechatronic unit on side of gearbox 3-shaft gear-set configuration Appropriate positioning of the rear final drive and the PTO shaft for the front final driveWith a fitted length of less than 600 mm, the 0BZ gearbox is more than 150 mm shorter than the R tronic. Together with the engine's dry-sump lubrication system, it achieves sufficient ground clearance at the same time as providing a low centre of gravity for the vehicle while keeping within the baseline limit. The 0BZ 7-speed dual clutch gearbox is thus made to measure for the new MSS platform1) with mid-engine configuration and quattro drive. That platform is the basis for the Audi R8 (Type 4S) and the Lamborghini Huracán.1)MSS = Modular Super Sports-car 22 BackForwards Ξ ContentsDifferences on the 0BZ gearbox between the Type 4S and Type 42The illustration shows the 0BZ gearbox in the Audi R8 (Type 4S).Differential lock with modified locking characteristics for front final drive 0D4. For more detailed information on the differential lock refer to SSP 613. Flatter ATF cooler1) with deflector hood (crash guard)Parking lock emergency release operated from vehicle interior by mechanical cableAuxiliary ATF cooler and oil temperature regulator dispensed with643_036Different transmission ratios for the PRO shaft for the front final drive 0D4 • Basic transmission ratio on V10: 28 : 23 • Dynamic transmission ratio on V10 Plus: 28 : 21ATF drain and inspection plug with bayonet fixing (not to be introduced at market launch)Gearbox control unit 1 – J743 is integrated in the immobilizer. New software functions. Refer to pages 17 and 71.1) he installed height of the ATF cooler on the Audi R8 (Type 4S) is lower than on the Type 42. The overall cooling concept on the Audi R8 T (Type 4S) has been redesigned and substantially improved so that no additional ATF cooler (air/oil heat exchanger) is required by either engine variant.23 BackForwards Ξ ContentsComponent overviewElectrical connection/circuit board for parking lock moduleParking lock mechanism and parking lock emergency release mechanismElectro-hydraulic parking lock • Parking lock moduleFinal drive with differential lock • The locking characteristics have been adapted to the different quattro drive concepts (Type 42/ Type 4S). • For more detailed information on the differential lock refer to SSP 613.Dual clutch24 BackForwards Ξ ContentsParking lock gearElectronic gearbox control module • Gearbox control unit 2Gear set and gear actuator • Hydraulically operated selector platesElectrical connection of mechatronic unitElectro-hydraulic gearbox control module • Mechatronic module • Gearbox control unit 1Auxiliary hydraulic module • ATF pump • Electro-hydraulic control unitElectrical connection for auxiliary hydraulic moduleElectrical connection for auxiliary hydraulic module643_038 25 BackForwards Ξ ContentsGearbox cross-section – gear set/gear train configurationA dual clutch gearbox essentially consists of 2 gear train subsets and the two associated clutches, K1 and K2. Gear train subset 1 carries the uneven gears 1-3-5-7, and gear train subset 2 the even gears 2-4-6 and reverse gear. In operation, only one gear train subset is transmitting power at a time, while on the other gear train subset in each case the next gear required is pre-engaged. If, for example, the vehicle is accelerating in 3rd gear, the next gear required is 4th gear on gear train subset 2. Gear changes are performed by switching power transmission from one clutch to the other in each case. In the above example – changing from 3rd to 4th gear – clutch K2 is engaged while clutch K1 is simultaneously disengaged. That process is referred to clutch overlap or overlap gear shifting. The entire sequence takes place at lightning speed in only a few hundredths of a second. Thus the dual clutch gearbox enables fast gear shifting virtually without interrupting power transmission.Rear axle final driveDifferential gear with differential lockSpur gear for driving ATF pumpC2Dual-mass flywheel for isolating rotational vibrationC1CrankshaftFront final drive input shaft • The final drive input shaft is also referred to as the PTO shaft. PTO stands for "power take-off". Different output shaft transmission ratios on Type 4S • Basic transmission ratio on V10: 28 : 23 • Dynamic transmission ratio on V10 Plus: 28 : 2126 BackThe rear final drive uses bevel gears without hypoid offset. That means that the sliding forces between the meshing teeth are smaller than with bevel gears with hypoid offset. This design enables the use of a common oil system using lowviscosity ATF for all functional transmission sub-assemblies. The differential has a differential lock using a design carried over from the R tronic. More detailed information on the differential lock can be found in SSP 613. The locking characteristics have been adapted to suit the all-wheel drive concept concerned (on the Type 42/Type 4S).Forwards Ξ ContentsPinion shaftR1 4 5Output shaft 1Input shaft 1Output shaft 26 2Input shaft 27 3Gearbox unit 1 Gearbox unit 2643_039 27 BackForwards Ξ ContentsDual clutchThe dual clutch is the central functional component of the dual clutch gearbox. It transmits the torque to the relevant gear train subset.Design featuresThe dual clutch consists of 2 wet-type multi-plate clutches, K1 and K2. The two clutches are mounted in line with each other and have the same dimensions and the same number of plates as one another.Power transmission path in the dual clutchThe engine torque is transmitted from the dual-mass flywheel via the dog clutch to the coupling housing and from there to the clutch housing cover. The clutch cover positively interlocks with the clutch hub. The clutch hub, in turn, is connected to the inner plate carriers of the two clutches. Clutch K1 transmits the torque to its outer plate carrier, which in turn positively interlocks with input shaft 1. Clutch K2 transmits the torque to input shaft 2.Reluctor for engine speed sensorClutch housingPiston K2C2C1Piston K1 Clutch housing coverMEngineClutch hub – inner plate carrier Clutch carrierDriving device28Input shaft 1Input shaft 2643_040 BackForwards Ξ ContentsDual mass flywheelDriving deviceClutch coverClutch housing coverC2 C1Ring gear – for starter Clutch hub – inner plate carrierATF pump drive Clutch carrierDowel sleeveSections through fixed components – gearbox housing Power transmission path from dog clutch to clutch643_041 29 BackForwards Ξ ContentsDual clutch oil systemThe oil entire oil system for the dual clutch is supplied via the clutch carrier by means of what is referred to as a rotational feed system. The dual clutch is mounted on the clutch carrier by 2 needle roller bearings. See Figure 643_041 on page 29. The clutches are supplied with the control pressure (clutch pressure), cooling oil and centrifugal oil for dynamic pressure equalisation via 4 oil channels. Five Torlon rings form the rotary seals for the 4 oil channels. In order to counterbalance the effect of dynamic pressure build-up with increasing rotational speed, each of the clutches has a pressure equalisation chamber (centrifugal oil chamber). The following functions are associated with the dual clutch: • • • • • • • • • • Clutch control Dynamic pressure equalisation Start-up Power flow reversal Clutch cooling Clutch control at standstill (creep control) Overload protection Safety shut-off Microslip control Clutch adaptationBasic information about those functions is provided in SSP 386 – 02E S tronic 6-speed dual clutch gearbox.Clutch coolingEach of the two clutches has a separate and demand-based cooling and lubrication oil supply (clutch cooling system). For that purpose, the centrifugal oil temperature of each clutch is detected by a separate temperature sensor (G658/G659) the readings of which are referred to for controlling the cooling system. refer to page 75. The supply of oil for cooling and lubricating the clutches is provided via the centrifugal oil chamber in each case and also supplies the centrifugal oil chamber with oil. A special feature of the clutch cooling system on the 0BZ gearbox is that the cooling oil supply for clutch K1 is provided by the mechatronic unit and the cooling oil supply for clutch K2 is provided by the auxiliary hydraulic module. The clutch cooling system for clutch K2 is controlled by cooling oil valve 2 N448, which in turn is controlled by gearbox control unit 2 J1006.Clutch pressure, clutch K1 Mechatronic unit for dual clutch gearbox J743Clutch pressure, clutch K2Clutch cooling system for clutch K1 Gearbox control unit 1 registers the centrifugal oil temperature of clutch K1 by means of the temperature sensor G658 and calculates the control current for cooling oil valve 1 N447.Clutch cooling system for clutch K2 Gearbox control unit 2 registers the centrifugal oil temperature of clutch K2 by means of temperature sensor G659 and sends the reading to gearbox control unit 1 as a CAN message. Gearbox control unit 1 calculates the required control current for cooling oil valve 2 N448 and sends the information back to gearbox control unit 2. Gearbox control unit 2 then applies that specified setting to N448. See also the following sections: hydraulic circuit diagram, schematic diagram and description of solenoid valves.Clutch cooling oil/centrifugal oil, clutch K130Clutch cooling valve 2 N448 Cooling valve 2 for clutch K2 BackForwards Ξ ContentsClutch monitoringThe clutch pressure of the two clutches is permanently monitored by gearbox control unit 1 – J743. If the pressure deviates from the specified clutch pressure, the clutch concerned is de-pressurised by means of a safety cut-out. Refer to page 66. The clutch temperature of the two clutches is constantly monitored by the two gearbox control units J743 and J1006. As already mentioned, the two temperature sensors, G658 and G659, are referred to for calculating the clutch temperature and controlling clutch cooling in each case. If a centrifugal oil temperature of around 170 °C is exceeded, the instrument cluster displays the warning "Gearbox too hot. Please adjust driving style." and a corresponding entry is registered in the event memory. Refer to page 75.Pressure equalisation chamber – centrifugal oil chamber, clutch K1Clutch piston, clutch K1 Pressure equalisation chamber – centrifugal oil chamber, clutch K2Pressure chamber K1Clutch piston, clutch K2Pressure chamber K1KD2 KK1KK2 KD1Torlon ringC2 C1643_042Key: KD1 KK1 KD2Auxiliary hydraulic module Clutch cooling oil/centrifugal oil, clutch K2Clutch pressure oil channel, clutch K1Cooling oil/centrifugal oil channel, clutch K1Clutch pressure oil channel, clutch K2KK2Cooling oil/centrifugal oil channel, clutch K231 BackForwards Ξ ContentsGear train and gear setSpecial featuresThe gear set of the 0BZ gearbox has the following special features: • Reverse gear is implemented without a separate reverse drive gear or reverse shaft. • The parking lock gear is combined with the sliding collar of gear set R/4 in a single unit. • There is a separate output shaft for driving the front wheels.Output shaft 1Sliding collar R/4 with parking lock gearInput shaft 2Input shaft 1Output shaft 2Pinion shaftDifferent output shaft transmission ratios on Type 4S • Basic transmission ratio on V10: 28 : 23 • Dynamic transmission ratio on V10 Plus: 28 : 21643_043Figure 643_045 opposite shows how the two output shafts 1 and 2, the pinion shaft and the PTO shaft for the front final drive are permanently positively engaged.Front final drive input shaft • The final drive input shaft is also referred to as the PTO shaft. PTO stands for "power take-off".32 BackForwards Ξ ContentsDisengageThe parking lock gear is located on the sliding collar of gear set R/4. The sliding collar, the synchromesh hub and output shaft 1 are locked together rotationally. When the parking lock is engaged, output shaft 1 is locked.Reverse gearThe reversal of rotation direction for reverse gear is achieved by means of the synchroniser gear for 2nd gear. The synchroniser gears for 2nd and reverse gears are permanently engaged. In reverse gear, the torque is transmitted from input shaft 2 via the idling synchroniser gear for 2nd gear to the synchroniser gear for reverse gear. The direction of rotation of output shaft 1 is thus opposite to what it is in the forward gears.Reverse gearOutput shaft 1 Synchro hub Sliding collar R/4 with parking lock gear Input shaft 2Output shaft 22nd gear pinion643_044Interconnection of the shaftsOutput shaft 1Output shaft 2Pinion shaft643_045 33 BackForwards Ξ ContentsGear shifting and gear-shift actuatorsGear changing is performed by means of 4 hydraulically operated selector forks referred to as gear-shift actuators. Each gear-shift actuator consists of a selector fork with a selector plate at each end of which is a single-action hydraulic cylinder. On the selector plate there is also a bracket holding sensor magnets and a catch. Pressure is applied to the hydraulic cylinders so that they move the selector forks to the left or right (gear engaged), depending on the gear to be selected, or to the centre position (neutral position). Once the gear/neutral position is engaged, the hydraulic cylinders are de-pressurised. The gears are kept engaged by the undercut of the dog teeth and the catches on the selector plates. In neutral position, the selector plates are held in the centre position by the catches. The sliding collars also have a catch for the neutral position. When the vehicle is stationary, 1st gear is always engaged on gear train subset 1. On gear train subset 2, 2nd or reverse gear may be engaged depending on the immediately preceding driving scenario. If the vehicle is braked to a standstill having been travelling forwards, 2nd gear remains engaged. Reverse gear is not engaged until transmission setting R is selected or if the engine is switched on again after being switched off and transmission setting D or R is selected. If, for example, the engine is switched off immediately after reversing, reverse gear remains engaged likewise.Selector fork 1, gear-shift actuator A 5th/1st gearSelector plate catch Selector fork 1, gear-shift actuator A, gears 5/1Selector fork 4, gear-shift actuator D, gears R/4Gearbox unit 1 Gearbox unit 2643_04634 BackForwards Ξ ContentsGear shift monitoringFor the gearbox to function perfectly, the exact positions of the selector forks must always be known to the gearbox control unit. Four travel sensors determine with the aid of sensor magnets attached to the selector rods determine the positions of the relevant gear-shift actuators/selector forks. Refer to page 74.643_047The measurements taken – actual positions of gear-shift actuator A (B/C/D) – show the gear-shift travel in millimetres. Refer to page 74.Travel of gear-shift actuatorSensor magnet for travel sensor G4901) for gear-shift actuator D for gears R/4 Sensor magnet for travel sensor G4871) for gear-shift actuator A for gears 5/13rd/4th/5th/6th gear engagedNeutral position1st/2nd/7th/Reverse gear engaged643_102In the event of malfunctions or invalid shift positions, the gear train subset concerned is hydraulically disabled by means of the safety cut-out. Refer to page 66.Selector fork 3/gear-shift actuator C, gears 3/7Sensor magnet for travel sensor G4891) for gear-shift actuator C for gears 3/7 Sensor magnet for travel sensor G4881) for gear-shift actuator B for gears 2/6 Selector fork 2/gear-shift actuator B, gears 2/6Due to manufacturing tolerances, the limit positions and synchronisation points of each gear have to be learned by gearbox control unit 1 – J743. Appropriate functions are provided on the vehicle diagnostic tester for doing so.1)See also page 75. 35 BackForwards Ξ ContentsPower transmission path in gearbox1st gearGearbox unit 1 Gearbox unit 2Input shaft 1 Input shaft 2 Pinion shaftR1 4 5Output shaft 1C2 C12PTO shaft for front final drive637Output shaft 2643_0482nd gearR C2 C11 4 5236637643_049 BackForwards Ξ Contents3rd gearR C2 C11 4 524th gear637643_050R C2 C11 4 52637643_051 37 BackForwards Ξ Contents5th gearGearbox unit 1 Gearbox unit 2Input shaft 1 Input shaft 2Pinion shaftR1 4 5Output shaft 1C2 C12PTO shaft for front final drive637Output shaft 2643_0526th gearR C2 C11 4 5238637643_053 BackForwards Ξ Contents7th gearR C2 C11 4 52Reverse gear637643_054R C2 C11 4 52637643_055 39 BackForwards Ξ ContentsParking lock – mechanical functionAs there is never any drive engaged when the engine is not running (both clutches K1 and K2 are disengaged), the 0BZ gearbox requires a parking lock, as is usual with automatic transmissions. The parking lock mechanism is the same as the already familiar mechanism with parking lock gear and a locking pawl that is actuated by spring-loaded, tapered sliding sleeve. A special feature on the 0BZ gearbox is that the parking lock gear is not located on the gearbox output shaft, as is normally the case, but instead is integrated in sliding collar R/4. See page 33.Engaging the parking lock – P-ONThe parking lock is engaged by the force of the parking lock spring. The parking lock spring forces the parking lock piston together with arrester element and tapered sliding sleeve between the bracing plate and the locking pawl. As a result, the locking pawl is pressed against the parking lock gear. The claw engages in the teeth of the parking lock gear and locks it in position.Parking lock piston Parking lock spring Locking element with shoulder and holder for sensor magnetStriker block Spring-loaded tapered sliding sleeve Pawl Pivot mounted in gearbox housingResetting springParking lock solenoid N486Parking lock solenoid N573 – Parking lock engagement valve Hydraulic pressure acts on parking lock piston643_078Disengaging the parking lock – P-OFFThe parking lock is disengaged by the hydraulic force of the parking lock piston. The parking lock piston pulls the tapered sliding sleeve back against the force of the parking lock spring. The return spring forces the locking pawl out of engagement with the gear teeth and holds it in that position.643_079 40 BackForwards 1st stepΞ ContentsEngaging the parking lock if pawl and gear do not mesh1. step: If the claw of the locking pawl clashes with a tooth of the parking lock gear, the tapered sliding sleeve is still forced between the bracing plate and the locking pawl by the preloaded spring force. The tapered sleeve is spring-loaded and presses the locking pawl against the tooth of the parking lock gear.2nd stepTapered sliding sleeve – springloadedClaw and tooth clashing643_0802. step: As soon as the vehicle rolls a little and the parking lock gear rotates slightly, the locking pawl snaps into engagement with the parking lock gear because the tapered sleeve is preloaded by the force of the spring. The parking lock is engaged.643_081Holding the parking lock in position P-OFF with the parking lock solenoid N486A Keeping parking lock disengaged If the parking lock needs to remain disengaged after the engine is switched off, the parking lock piston has to be held in the P-OFF position by the parking lock solenoid N486. To hold the lock in position P-OFF, N486 remains energised after the engine is switched off. That means that the armature of N486 remains pulled in against the force of the spring (Figure A). In that position, the 3 ratche