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Matt, Mechanical Engineer
Category: Audi
Satisfied Customers: 22727
Experience:  BEng hons Mech engineering, in auto industry 22 years
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A6 Rear Diff is locking when undertaking tight manoeuvres and

Customer Question

A6 Rear Diff is locking when undertaking tight manoeuvres and causing a very mild vibration when straightening out. Audi dealer says I need a new one and has quoted £4600! Are there any other options? (It a 3.0 TDI manual 2006 with 80K on the clock)
Submitted: 3 years ago.
Category: Audi
Expert:  Matt replied 3 years ago.

thats a ridicolous amount

a good used diff from an Audi breakers will be about £200 which is probably the cheapest option


Customer: replied 3 years ago.

Hello Matt

I didn't need an expert to tell me that. I am looking for full information, all the facts and figures about the problem. How common? Is it a design fault? How long will the existing diff last? Can it be managed with careful driving? What if I change the oil and if so what type of oil should be used? If I buy 2nd hand diff how long will that last? Is there a repair option? I appreciate that there are probably no definite answers to these questions but I am asking for your expert opinion, with some in depth discussion of the issues. Thank you. Neil




Expert:  Matt replied 3 years ago.

Hello Neil

Thats fair comment

there's no offical recall for the diff on these so its not a 'recognised' fault by Audi although I have heard of this occuring on another occasion but that was on the RS6 so higher power

its well worth trying an oil change before getting into a diff swap

drain the oil off through some paper towel to catch any debris as this will provide further clues to the condition of the diff

the correct oil as a replacement needs to be a 75W90 full synthetic type meant for limited slip differentials

the capacity is supposed to be 2 ltrs but unless its completly dry you'll typically only get 1.5 ltrs in there

there's a good how to here:

as for repair then its possible and any differential specialist will be able to strip it down and rebuild it with new clutch plates and bearings however I'd expect the bill to be about £200 so its probably more cost efective to get a good used diff