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363 Service TrainingService Audi Q7-PowerTransmission /Transfer Case 0AQ Self-Study Programme 363 Audi Q7 - Power by the inventor of the quattro®.

The powertrain concept of the Audi Q7 offers impressive performance at high speeds in addition to outstand- ing dynamics, both on and off the road.

The permanent quattro four-wheel drive® with asymmetric, dynamic torque split ensures maximum traction and cornering stability. These features are essential to good driving dynamics and active motoring safety, par- ticularly when driving on paved roads and at high speeds.

The newly developed transfer case 0AQ is the centrepiece of the power transmission system.

This SSP deals mainly with the design and function of this new development.

363_001 Contents

Introduction

Drive concept ...... 4 Subassemblies overview ...... 6

Brief description of the gearbox

6-speed manual gearbox 08D ...... 8 6-speed automatic gearbox 0AT / 09D ...... 9

Gear selector mechanism

Automatic gearbox selector mechanism ...... 11 Manual gearbox selector mechanism (refer to SSP 299) ......

Transfer case 0AQ

Design / function of transfer case 0AQ ...... 16 Self-locking centre differential...... 18 Components overview / design / function ...... 19 Asymmetric basic torque distribution ...... 21 Asymmetric/dynamic torque distribution ...... 22 Chain drive ...... 26 Lubrication ...... 28 Oil supply / sealing ...... 30

Service

Service / special tools ...... 31

Useful information

Operating instructions ...... 32

This self-study programme teaches the design and function of new vehicle models, new automotive compo- nents or new technologies. Reference Note

The self-study programme is not a workshop manual! All values given are intended as a guideline only, and refer to the software version valid at the time of publication of the SSP.

Please refer to the relevant service literature for current inspection, adjustment and repair instructions. Introduction

Drive concept

Rear axle differential 0AB

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As an SUV* with excellent on- and off-road The sub-assemblies step-up gear, front axle differ- driving dynamics, the Q7 is equipped as standard ential and transfer case are independent compo- with quattro four-wheel drive. nents. The powertrain has what is known as a "modular design". The running gear and the layout of the drive train sub-assemblies were adopted from the VW Touareg. The advantage of this modular design is that it ena- bles the ground clearance of an off-road vehicle to This configuration allows the engine to be posi- be increased. tioned directly over the front axle. Thus, the step-up gear and the transfer case migrate more towards the centre of the vehicle, favouring a well-balanced axle load distribution beneficial to driving dynamics. * SUV =

4 One of the primary development goals for the Audi Up to 85% of driving torque can be transferred Q7 was good driving dynamics on paved roads. mechanically, i.e. without EDL engagement, to the A special reduction gear and a mechanical differen- rear axle and up to 65% to the front axle. The new tial lock were dispensed with in favour of the rede- differential ensures optimal on-road driving dynam- signed transfer case and the newly developed self- ics. locking centre differential. When wheelspin occurs - off road or on icy surfaces The self-locking centre differential is already in use - the EDL control system engages and provides trac- in the Audi RS4 and S4, and features asymmetric/ tion in almost any driving situation. dynamic torque distribution.

Transfer case 0AQ

Step-up gear Automatic or manual gearbox

Front axle differential 0AA

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5 Introduction

Sub-assemblies overview

The following gearboxes are used:

Audi Q7 4.2 FSI: 257 kW (350 bhp), 440 Nm

Audi Q7 3.0 TDI: 171 kW (233 bhp), 500 Nm

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6-speed automatic gearbox 09D

Audi Q7 3.6 FSI: 206 kW (280 bhp, 360 Nm)

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6-speed automatic gearbox 0AT 6-speed manual gearbox 08D/ ML400 (expected SOP: 4th quarter 2006) (expected SOP: 2nd quarter 2006)

6 The front and rear axle differentials derive from the Front axle differential 0AA VW Touareg. Both differentials are manufactured by ZF Getriebe GmbH. The left-hand drive flange shaft has been extended to compensate for the asymmetric installed position of the front axle differential.

Thus, the additional torque resultant from the drive torque is transmitted symmetrically to the front axle. Negative effects on are thus elimi- nated.

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Rear axle differential 0AB Transfer case 0AQ was redesigned for use in the Audi Q7. The 0AQ transfer case was developed in conjunction with, and is manufactured by Borgwarner.

7 Brief description of the gearbox

6-speed manual gearbox 08D...

… is a conventional full synchromesh The 1st and 2nd gears are selected using a triple- countershaft-type gearbox, also known as a "3-shaft cone synchroniser. gearbox". The 3rd, 4th and reverse gears have a double-cone …derives from the VW Touareg, in which it has synchroniser. already proved successful. The 5th and 6th gears have a single-cone synchro- … is used for engines with up to 400 Nm of torque. niser.

The 08D gearbox was developed by, and is manufac- tured by ZF- Getriebe GmbH.

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Reference

For further information on the 08D gearbox, please refer to SSP 299.

8 The 6-speed automatic gearbox 0AT...

… is an electro-hydraulically controlled 6-speed The 0AT gearbox... planetary gearbox (multi-step automatic gearbox) with hydrodynamic torque converter and slip-con- …is a new development for the Audi Q7 optimised trolled converter lockup clutch. with regard to weight and fuel economy for engines with up to 400 Nm of torque. The hydraulic control unit (valve body) and the elec- tronic control unit have been combined in a unit, … belongs to the same family as the 6-speed auto- the so-called mechatronics. The mechatronics are matic gearboxes 09E and 09L located in the oil sump. The 0AT gearbox was developed by, and is manufac- tured by ZF- Getriebe GmbH.

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Other features: Reference – Special deep-seated ATF intake point and the large ATF capacity to ensure proper oil intake For further information on 6-speed during off-road use. automatic gearboxes 09E and 09L, please refer to SSPs 283/284 and SSP 325. – Extended gearbox breather pipe to prevent ingress of water into the gearbox even under adverse conditions.

– Large-sized torque converter and torque con- verter lock-up clutch. Note

– Integration of the gearbox into the immobiliser This gearbox will not be available at roll-out. system Further details will be published later in a sepa- rate SSP.

9 Gearbox code

6-speed automatic gearbox 09D…

… is a conventional electro-hydraulically controlled 6- The 09D gearbox... speed planetary gearbox (multi-step automatic gear- box) with hydrodynamic torque converter and slip- …derives from the VW Touareg, in which it has controlled converter lockup clutch. already proved successful.

The hydraulic control unit (valve body) is located in … is used for engines with up to 750 Nm of torque. the oil sump, while the electronic control unit is accommodated externally in the vehicle interior … belongs to the same family as the 6-speed auto- (under the right-hand front seat). matic gearbox 09G (see SSP 291)

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