Originally Posted by sexye92
im not sure if this applies to your diff, but i tried installing a quaife lsd in a customers car, it got it to go in but the way it was build and not able to shim the bmw diff, it had the ring gear way to tight against the pinion gear so there was zero backlash, needless to say i would not leave it in, i pulled it back out and put the stock back in
I've changed ring and pinions on v8 American cars and seen plenty of others installed by so-so shops and the backlash AND pinion depth has to be perfect or it will whine (or worse).
The ol' magnetic mount dial indicator (to measure backlash) as well as some test turning of the assembly to note the pattern of the ring and pinion gear contact area is required.
My 2c is that I'd never take a car to have a ring and pinion swapped unless a) they do a LOT of R&P gear swaps on various cars or b) they've actually done at least one R&P swap on the exact scenario/car I would be leaving with them.