4.10 Lsd R&r

[e30s4evr]

I just purchased a used 4.10 LSD with 160K miles of a '91 318is that was hit up front. It was caked in dirt on one side when I picked it up and the guy's explanation was that his CV joint blew and caused the mess...

  I cleaned the diff and pulled the cover off to see clean gears with no chipped teeth and no sludge buildup. The teeth actually have their machining marks intact showing no sign of wear. No buildup on any of the gears either. There was just a very thin layer of black deposit on the walls of the housing and the little oil that was left in was pretty clean. There is very little play in the input shaft -less than 5 degrees. But as I turn the output flanges as fast as I can by hand it makes a wooshing noise -not sure how quiet it is supposed to be without any fluid.

  Before I put it on, how do I make sure this is a good diff and what seals and bearings can I replace without any special tools? The whole 'shady' nature of the deal makes me suspect if this was a noisy diff and that's why it was for sale...

Thanks,
Narayan

[b318isp]

It sounds like there is bearing wear if it whooshes, but often you can get thousands of miles out of the diff like this. If the there is any lumpiness or grating then forget it.

[e30s4evr]

No lumpiness or grating! Can this bearing be replaced without special tools?

[b318isp]

If it is the pinion bearing then it's a pro job. If its the side bearings then it is potentially DIY but to be honest, it will be hard to pinpoint which.