I have a 1980 RX-7 and my rear end locked up. I was driving home and it started humming and vibrating. It seems like a bearing failed but I haven't taken it apart yet. I jacked it up and tried spinning the tires by hand and they won't move. I slowly released the clutch in first and heard a grinding noise so I stopped. This is my daily driver and was wondering what year & parts interchange. The car is stock and I just want to get it back running without spending much $$. I'm I better off picking up a complete rear end and swapping it or rebuilding mine. Any help would be appreciated. Thanks

 

Gotta take the rear out and inspect the damage. Hopefully axel bearings didn't break too, those are a pain to replace. Removing a rear is not complicated, just a lot of bolts and elbow grease. I do believe the 81-83 LSD would fit into an 1980. Might as well upgrade to LSD while the rear is out.

 

Thanks for the info. I'll have to look into the 81-83 LSD. Any other tips? Iv'e never worked on a differential before.

 

Jack up rear. Take off rear wheels, rear brakes. Drain diff. There are three (four?) bolts holding the axel flange on. Take those off. Pull axel out. Sometimes they slide right out, othertimes you gotta hit it with a block of wood an mallet. Unbolt driveshaft from rear. Slide forward about 1/2". If you remove driveshaft, trans fluid will come out tailhousing. Remove the bolts holding diff onto rear end assembly. I usually hit it with the aforementioned block of wood and mallet to crack the silicone seal and break it loose.

Diff is heavy, be careful. Pull it out and bench press that puppy onto your chest and roll onto the ground onto a piece of carpet. Pull carpet out under car and bingo, inspect diff.

Now is an Excellent Opportunity to put a 4.444 ring and pinion in there

 

if I had one I'd put a 4:30 or 4:44 in mine