Knock - Rear Diff?

[SaintJon]

Hi all, I have a random metallic knock noise every so often (maybe every 10 mins?) from somewhere near rear passenger side wheel. Often when gently accelerating in slow traffic. Had look underneath as suspected loose exhaust or suspension mount. Couldn't see anything there but rear diff has signs of oil leak on both side output shafts, and slight up and down play on shafts that gives metallic noise...
Guess the seals have gone and running dry, how hard to replace? Could there be further damage (speculative I know) or could replacing seals and re topping with oil solve (not sure if this is exactly the problem, but not good!).
A4, 3.0 Quattro Avant, Auto, Tiptronic

Thanks for any advice!

 

[Cyrix]

If there is actual play in the shafts and you can hear a knocking I would imagine it is knackered (not uncommon)

Replacement is pretty easy, remove driveshaft and prop bolts, two (I think) bolts at the rear hold it to the subframe, remove the rubber mounting at the front and it should just drop out out.

 

[SaintJon]

Thanks, that's what I was dreading but expecting!

Any ideas where to get a new (refurbed/second hand) one and costs?

Thanks

 

[Cyrix]

I've actually got a good used one for sale from a low mileage 2.0 TFSI (B7) - The cambelt snapped and trashed the engine, so I stripped it for parts.

The diff code is "HUQ", your code will be in the build sheet on your service book or in the boot. It might be the same, not sure how many variations of rear diff there are.

 

[Paul @ Unit 9 Remaps]

im considering breaking my ASN 3.0 v6 quattro sport and the diff will be available

 

[SaintJon]

brilliant thanks both of you.

Will have a look through the books/tags this weekend and see what diff needs, plus may try topping up with oil first and see how runs...