Rear differential failure

kccougar · 3rd February 2011, 03:02

I have what I think is a rear differential that is failing. I have a fairly loud whine that sounds as if it is coming from the rear of the car - speed dependent but not gear dependent so I think I've ruled out the transmission. I've looked for leaks and found none. All the joints seem to be in good shape so I assume the whining is coming from inside the differential. What parts would be most likely to fail? And is it common to replace parts or the entire differential?

desmotesta · 3rd February 2011, 04:00

How about changing differential oil to see if that makes a difference.

jfoj · 3rd February 2011, 04:28

Possible driveshaft center bearing noise??

russap5 · 3rd February 2011, 05:58

Also could be wheel bearings. I would investigate further.

If you can, get the car running and up on a lift to diagnose from under the car.

Schuttsr1 · 3rd February 2011, 09:34

Whining for the diff is normally a bad pinion bearing. It is always worst and loudest in 6th gear. Is there any oil leaking fron the pinion seal? They tend to eat seals as they get looser.

gzig5 · 3rd February 2011, 15:45

I'd get it into a shop that knows what to look for. It could be any of the things mentioned but if it is the pinion bearing or anything else in the diff, you want to fix that immediately. The pinion bearing in mine went out but wasn't making significant noise. Eventually it broke teeth under load and the differnetial had to be replaced. That is not a cheap experience.

gsfent · 3rd February 2011, 16:08

Quote:

Originally Posted by gzig5

I'd get it into a shop that knows what to look for. It could be any of the things mentioned but if it is the pinion bearing or anything else in the diff, you want to fix that immediately. The pinion bearing in mine went out but wasn't making significant noise. Eventually it broke teeth under load and the differnetial had to be replaced. That is not a cheap experience.

Used diffs show up from time to time on ebay and other sites. Price around $750-$1000 or so these days. Of course, there is never one around when yours breaks and you need it right away.........
Regards,
Jerry

s62_740i · 3rd February 2011, 16:44

I know someone that have a diff for sale he is asking $800, miles on diff 71k, today is your lucky day. you can contact him his e-mail is curacrew@aol.com

gzig5 · 3rd February 2011, 20:29

Quote:

Originally Posted by gsfent

Used diffs show up from time to time on ebay and other sites. Price around $750-$1000 or so these days. Of course, there is never one around when yours breaks and you need it right away.........
Regards,
Jerry

Actually, I did have the opportunity to get a used one but being new to the car and not knowing what someone else's take off had seen in it's life I went with the Dinan. Either way it's an exercise that I would have preferred to avoid.

Greg

Schuttsr1 · 3rd February 2011, 22:14

750-1000 is crazy for a used diff. You can get a rebuilt one with a better lsd or a new one from bmw for not much more 1300 last I checked!

gzig5 when you purchased the dinan unit was it just the ring and pinion and you had to have some one install it or was it a complete unit. How was your milage affected by the gearing change?