Technical Service Bulletin
39 Gearbox: noises/vibrations in tight bends - Q7 and A8 vehicle models
39 24 69 2074857/1 August 30, 2024.
Model(s)

Q7
A8
S8

Year

VIN Range

Vehicle-Specific Equipment

All

Not Applicable

2009 – 2015
2017 – 2025
2011 – 2017
2019 – 2024
2013 – 2016
2020 – 2024

Q8

2019 – 2025

A8 e quattro

2020 – 2021

SQ7, SQ8, and
RS Q8

2020 - 2025

Condition
Customer states:
Noises/vibrations in tight bends.
Workshop findings:
The complaint can be reproduced. Compared with an identical comparison vehicle (especially tire size and
tire manufacturer), the complaint on the affected vehicle under identical conditions is significantly more
noticeable.

Technical Background 1
General information on all-wheel drive with self-locking center differential
The self-locking center differential is used in different gearboxes. The self-locking effect is generated using
worm gears. This design is characterized by a high locking effect. In conditions where the front and rear axle
have different grip levels, the axle that has more traction is able to provide up to three times more torque
than the other axle.

© 2024 Audi of America, Inc.
Internal

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All rights reserved. Information contained in this document is based on the latest information available at the time of printing and is subject to the copyright and other
intellectual property rights of Audi of America, Inc., its affiliated companies, and its licensors. All rights are reserved to make changes at any time without notice. No part of this
document may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, nor may
these materials be modified or reposted to other sites, without the prior expressed written permission of the publisher.

Technical Service Bulletin
With the Torsen differential, Audi has a permanent all-wheel drive system that provides superior driving
dynamics to many other switchable systems as it does not require any time to regulate the power, thereby
avoiding delayed responses. However, if there is a significant speed difference between the front and rear
axles in very tight bends and the vehicle is travelling at a high speed, the friction forces between the flanks of
the worm gear and the axial thrust washers in the differential are extremely high. Under these conditions, a
stick-slip effect can occur when the two surfaces contact each other. This can cause other components in
the vehicle to resonate and generate a vibration or hum (secondary effects).
This issue is merely a comfort-related complaint. The specified behavior is construction-related. No
damage occurs to components.
Please also note that there are other factors which can have a negative effect:
•

Wheels: different tread depth, hardness, width, summer or winter wheels, different tire manufacturers
(AO code)

•

Additional tension in the drive train due to wheel alignment

•

Possible noise transmission from assembly mountings

•

Possible noise generation/increase due to loose parts, parts under tension or incorrectly installed parts
in the interior of the vehicle or the chassis.

Production Solution
Not applicable.

Service
It may be possible to achieve an improvement by changing the gear oil in the transfer box. Please note
the precise approach as specified in the Workshop Manual.
The degradation of the friction modifier in the oil can result in a more pronounced stick-slip effect with
increased mileage. Replacing the gear oil in the transfer box also replaces the friction modifier and the issue
will be significantly reduced within 125 miles of replacement (depending on the driving profile).
Evaluation requires the gearbox oil to be between 40° C and 70° C (104° F and 158° F). Regarding
this complaint, higher and lower temperatures are not irregular. The workshop tester should therefore be
used to determine the exact gearbox oil temperature.

© 2024 Audi of America, Inc.
Internal

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All rights reserved. Information contained in this document is based on the latest information available at the time of printing and is subject to the copyright and other
intellectual property rights of Audi of America, Inc., its affiliated companies, and its licensors. All rights are reserved to make changes at any time without notice. No part of this
document may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, nor may
these materials be modified or reposted to other sites, without the prior expressed written permission of the publisher.

Technical Service Bulletin
The full effect of the oil change only becomes apparent after driving a distance of approx. 60 miles.

Warranty
Claim Type:

•

If the vehicle is outside of any warranty, this Technical Service Bulletin is
informational only.

Service Number:

3936

Damage Code:

0020

Labor Operations:

Remove and install rear transmission

3738 19xx

mount

Diagnostic Time:

See SRT with
associated operations

Replace gear oil

3990 5599

50 TU

GFF

0150 0060

Labor according to the
diagnostic log

Charge battery

2706 8950

See SRT with
associated operations

Extended road test after measure

0121 0199

According to punch
time

(Max 200 TU)
Claim Comment:

As per TSB 2074857/1

All warranty claims submitted for payment must be in accordance with the Audi Warranty Policies and

Procedures Manual. Claims are subject to review or audit by Audi Warranty.

© 2024 Audi of America, Inc.
Internal

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All rights reserved. Information contained in this document is based on the latest information available at the time of printing and is subject to the copyright and other
intellectual property rights of Audi of America, Inc., its affiliated companies, and its licensors. All rights are reserved to make changes at any time without notice. No part of this
document may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, nor may
these materials be modified or reposted to other sites, without the prior expressed written permission of the publisher.

Technical Service Bulletin
Additional Information
All part and service references provided in this TSB (2074857) are subject to change and/or removal. Always
check with your Parts Department and/or ETKA for the latest information and parts bulletins. Please check
the Repair Manual for fasteners, bolts, nuts, and screws that require replacement during the repair.
©2024 Audi of America, Inc. All rights reserved. The information contained in this document is based on the
latest information available at the time of printing and is subject to the copyright and other intellectual
property rights of Audi of America, Inc., its affiliated companies, and its licensors. All rights are reserved to
make changes at any time without notice. No part of this document may be reproduced, stored in a retrieval
system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or
otherwise, nor may these materials be modified or reposted to other sites, without the prior expressed
written permission of the publisher.

© 2024 Audi of America, Inc.
Internal

Page 4 of 4

All rights reserved. Information contained in this document is based on the latest information available at the time of printing and is subject to the copyright and other
intellectual property rights of Audi of America, Inc., its affiliated companies, and its licensors. All rights are reserved to make changes at any time without notice. No part of this
document may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, nor may
these materials be modified or reposted to other sites, without the prior expressed written permission of the publisher.