[Biturbos4] A whine from the rear

[j.koenig]

Speaking as a guy who's now replaced all four wheel bearings, I think you would tend to 
notice a change in the sound due to side loads (steering/weaving) long before you would 
notice throttle-induced change (if ever).  I'm no expert, but it sounds to me like a 
classic ring and pinion issue.  I hope I'm wrong.  Good luck!
John


----- Original Message ----- 
From: "Chris Newbold" <chris at newbold.org>


Just shy of 65k miles, and I'm starting to notice a whine originating
somewhere in the rear. The whine...

  o is loudest between 65-70MPH
  o is unaffected by gear: 3rd, 4th, 5th or 6th and the pitch is identical
  o is unaffected by steering inputs
  o is strongly correlated to throttle inputs:
     - it stops if you gently lift and coast
     - it stops if you dip in and accelerate
     - it returns in steady cruise

The only things which satisfy all of these observations are:

  o rear differential
  o center drive shaft bearing (do the B5s even have these?)