Quote:Naw, never. I've had many cars with warn diffs, they don't get worse. Even some Datsun.

Of course it could go bad for other reasons, like:
- run it out of oil
- donuts
- full-throttle starts and sticky tires

Strange question, but was the other car you got the diff out of a manual or auto, & is your's a manual or auto. It sounds like it's gone through the case hardening on the ring & pinion, so i'd hunt up a A10 510 then install the complete rearend. Grab the 510 tailshaft, because it needs to be shortened & the front yoke changed over to suit the gearbox. I don't think the stock 210 rear yoke works with the h165. Or turn the radio up

As far as I know the rear end was the same as the one I had before. Im not sure if the other car was manual or auto. Mine is manual. I do know that the car it came from belonged to an elderly women who got t-boned and died in the car. The wrecker told me the passenger side door was in the driver's seat. It may be possilbe that the rear end is haunted. I did have my friend and his dad (the own a body shop) look at the car. We jacked the end up and put it in gear and we were able to rotate either wheel backwards while the other was going foward. blah blah blah, the diagnosis was that the two "side gears" are messed up. Im not a mechanic so i may be butchering terms.

This might sound stupid as a box a chocolates, but take two banannas, shove them skin and all into the differential. Now drive around for a while. Does the sound get less/go away? Then it's the gears. Banannas act like a very good cushioning oil in diffs, and will generally shut them up for long enough that when you trade the car neither salesman nor the next owner will notice for some time that something is wrong....

It stinks like hell when you do drain it eventually...