I've got an '82 LSD Rear with Disc brakes and drive shaft sitting in the garage. I've got a drum brake non-lsd 84 GS. I was thinking of just swapping all over, but I was also thinking of just switching the LSD insides and keeping the drum brakes since the car brakes well anyway. My question to the group is: is that possible and relatively easy? Can I just open up the rear end and swap out the insides? I'm sure I have to remove the rear axles to get to everything. Is it worth it or should I just swap out the whole thing because it's too much trouble?

 

No you can't. The '82 has "small" axles (79-83) and the '84 has "large" axles (85-85, both 12A & 13B). The axle splines must match the side gears in the diff. While you can buy the correct side gears new from Mazda, cost is high and the effort makes it unreasonable.

Swapping the whole rear end into your car is much more feasible. You will want to use the '82 driveshaft (the flange changed in '83) and e-brake cables, but with those items the swap is cake.

 

Can you clarify that? It looks like you made a typo. The '84 and '85 cars have large axles and the 79-83 cars have the small ones?

 

I think he ment to say 84-85


My question is I have an 82 GSL rearend, but I have a 83, but I just bought a new driveshaft and dont want to get a new one. Is there a way I can swap the flange on the rearend? What are my options?

 

D'oh! Yes, that's what I meant. 79-83=Small Axle; 84-85=Large Axle. The small axle setups are actually stonger because the axle housing is stiffer. The flange was: 79-82=Small Flange; 83-85=large flange. That's no typo...the flange changed in 83 and the axle size changed in 84.

Sure, but it's a bit more involved, particularly if you mean to do it "right". I won't get into the details -- you can buy entire books on the subject -- but even a quick and dirty hack is more work than finding the right driveshaft.