A year or so ago I had this bit of an experience on some snow.

Now I have a droning noise at the rear wheels consistently at 50mph. Just got off the phone with the mechanic who told me it's the rear differential and that it has to be replaced (they don't do rebuilds).

New diff from Audi is $2800. I don't want to drop that right now unless I really really have to. Is there something short-term I can do? If I do have to replace, are there aftermarket parts to look at?


(2003 A4 3.0q manual)

 

Mechanic replaced a wheel bearing, but it made no difference, so it looks like I'll have to replace this thing after all

And insult to injury, driver's door and entire passenger side got keyed yesterday....

 

Are you sure the noise is coming from the rear end not from the center diff?

 

I can't say 100%, but it's really most audible with the rear seats folded down during a drive test.

How can I test if it's the center?