Diff windup in reverse & judder when pulling away [Archive] - Audi Forums

: Diff windup in reverse & judder when pulling away


icade
04-16-2011, 01:44 AM
Hi, another newby here.
I have just bought a 56 plated Q7 SLine and I seem to have a couple of problems.
1). When performing 3 point turn type manouver in reverse the diff seems to windup and judder/ slip. This did not seem to happen in my friends Q7 that I test drove before buying mine.
2) When pulling away from a junction or when pulling away after slowing down there are a series of noticeable thuds/ dull bangs like the transmission is slipping.
This does not happen every time but will happen several times on a journey.
(No it didn't do it on the test drive I had before I bought the vehicle 2 days ago)
The number of thuds can be from 2 to 5/6 and seem to be sequential as if from a rotating component.:(

icade
04-24-2011, 02:11 PM
Further to my last post, I have noticed that the front tyres are different to the rear in size.

The fronts are 275/45/20 and the rears are 295/40/20.

Anyone any thoughts as to if this is enough to cause the problems I am experiencing?

Obviously the rolling circumference of the 275/45 is about 36mm longer on the front than rear and could be causing the windup/banging/juddering?

a8 tech
04-24-2011, 04:10 PM
o yes and possible damage to the rear differential with differing wheel speed input

icade
04-30-2011, 04:45 AM
I have had the 295/40 rears changed to 275/45 Bridgestones and this seems to have sorted the juddering and diff windup. :) Supplied FOC by dealer...

Just need to find out if the diff has suffered from the problem. The tires I took off were only 1/4 worn so it may not have covered to many miles on them.

Also did front to back swap so the 275 Kumhos that were on the front are now on the rear, and what I thought had developed into a wheel bearing hum at the front appears to be them giving off road noise as it has shifted to the back end...