I've done pretty much everything else under the sun, but never rebuilt a tranny/diff before. Just picked up an 85 with a rear LSD/disc swap on it before the holiday break. Almost certain the pinion bearing is toast, and it only takes 5-10 ft-lbs to break one side free from the other on the rear wheels. So I'm certain it needs a rebuild, new clutch discs perhaps? Trying to turn the car into an autocross/track car and looking for somebody who has some experience to help me out in the rebuild to make sure I don't f up anything My garage is pretty well equipped, complete with a 2-post lift which I'd be more than willing to offer up the use of to anybody willing to help me out. Just want to get rid of that horrible grinding noise!
Oh yeah I'm in the Lynnwood area, thanks!

 

Jeff's Mazda in Puyallup on Canyon road built mine, A tight rear end in a FB makes autocrossing incredibly hard because the car wants to plow. I ending up selling mine and getting a stock 84-85 lsd pumpkin. The ideal setup would be a torsen pumpkin from a miata, pretty much plug and play, I know JEB, kill no cone had one for a while. If your running stock power or slightly above, a used rear end will work.

 

Thanks for the response! Just looking to bring it back to stock specs, the main concern right now though is the pinion bearings, which are making a racket. The rear end is off an 83 or earlier car because it's got the smaller bearings, does the miata torsen swap in the same as it would a true 84-85 rear end?