Reconditioned Diff Whine

[Elanman99]

Jack

I too have a diff that has variable backlash. I traced the cause to the main carrier surface that the CW fixes to having a 'wobble'.

Its hard to see how the flange could be anything other than true, even harder to imagine how it got that way.

I was able to surface grind the mounting face myself so its OK now. I reassembled the diff and tried to set it up by bluing etc but eventually reached the conclusion that now the pinion needs shimming. According the the manual a special tool is required so I have actually left it with a company (in the UK).

Given the right tool I am sure I could set the diff up as good as a 'professional' but what I don't have is hands on experience. I might get the mesh correct to the manual but apparently even then there is no guarantee that it wont whine in the car.

Ian

[Quart Meg Miles]

Meg..sound proofing above the diff.....do tell more....what sort of material, where and how installed? Robert

I'll start a new thread in a week or three when I've found some diagrams, if I actually made some. If not I'll reverse-engineer it.

[jk952]

I loosened everything again, checked all surfaces, cleaning etc. I did notice an unven edge on one of the bearing caps in a couple of areas, not something I did, looking like a ding from the side to separate the caps, plus misc. oddities, so I cleaned all these surfaces up to flat. Not sure if that was the problem but could potentially cause a misalignment. Reset everything again making sure the bearing races were reseated after any adjustments of side. The whole thing measured better when done.
By the way I measured that one side hole diam. adjustment works out to .002 inches in width change, usefull for maintaining the clearance.
Before I did anything however I set up the rudimentary bench test ( hopefully in the pict.) for noise using the wood lathe drive that has been collecting dust for numerous years. Had another diff for reference too. So when done the red one was the same noise level as the black one, about a 4 db improvement. Noise meter was surprisingly steady. Not a terribly scientific test but better that just putting back in the car and hoping. The frequency was lower based on the highly empirical ear test, (don't have a real time full freq. noise analyzer!)

Now to put back in the car....

Jack