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Could anyone who specialises in diffs fix my issue?


24 Jun 2013
I have found what the issue is with my ongoing knocking issue but I cant fix it as I am no good.

The issue is it knocks when going on and off throttle. A chap in the USA has had the same issue as me and has sorted it and said this which makes little to no sense to me:

Well after a bit of effort I have hopefully solved the differential problem I was having. Just to recap, my diff was making a progressively louder clacking noise when accelerating or decelerating. After checking for loose trans/engine mounts and other suspension parts I finally narrowed it down to the differential.

At this point decided to readjust the shims beneath the cups. The procedure I used was similar to that described for the GT2 (couldn't find any info for the 996tt tip). The first step was to determine the total width of S1 + S2. To do this I added 1mm to both and measured the remaining play to be 0.5mm. To this I added 0.35mm preload for a S1+S2 total of 2mm +0.5mm +0.4mm. In the end the optimal backlash was found by using a 1mm stack height for S1 and 1.85mm for S2 (as close as I could get to 1.9mm using the shims on hand).

Would someone who sees diffs day in day out be able to sort this out? From what I understand it appears to just need some sort of shim backlash fix type job?

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