Diff rebuild

[tsmcg161]

Ive acquired a groaning noise that seems to be coming from the passenger side rear wheel. I serviced the diff a couple of days ago with 75w-140 and still have groan noise. Are these diffs rebuildable or hunting down a used one a better option? Would this be a good time to put in a non LSD with a different ratio or stick with what came on the car?

[TheStigg]

Does it groan all the time or just when making slow tight turns?

[tsmcg161]

Slow tight turns only.

[Sansouci]

Sounds like a wheel bearing......

[e30luv318i]

3.15 lsd is a very desirable diff even if you decided to replace with a different diff your diff with noise still has significant value. You can use any diff from a 740i/l or 540 just know if you use a 740 diff (2.93) I believe? Your going to lose off the line acceleration

[tsmcg161]

I'm opening her up tomorrow and checking the bearings. I'm very suspicious its a possible bearing.

[TheStigg]

Groaning like that sounds more like a stick-slip instability condition in the LSD clutch pack, which is a common problem with clutch type LSD's. Rather than tear it down, do another drain & fill and put a full 5 or 6 oz. bottle of LSD conditioner in it and do a bunch of tight figure-8's in a parking lot to work it in. It should resolve itself without a tear down.

[tsmcg161]

75w-140 with the additive did the trick. Thanks to all who chimed in.