legacycentral bbs

Alright, have a bit of a 'situation.' A friend of mine has a WRX with a 3.9 STi 6mt. He needs a 3.9 rear. I have the stock rear diff out of my '92 SS. He would like to be able to use his thicker WRX axles though. My question is can the internals from a '92 SS rear diff be put inside the case of a WRX rear diff such that he could use his stock rear axles?

not happening. The internals are why he couldn't use the axels, not the case.

what about just swapping out the ring and pinion?

Why don't you just swap out the stubs...


And I don't think there is really that much of a difference between axles either...as far as strength

Ring and pinion isn't too bad. Just make sure the backlash is correct.

Swapping the ring and pinion is the way it is done for the 6 speed swap. I have the instructions on how to set the lash, I can drop them in the mail for you.

Anybody have a PDF or tips on backlash settings in the LSD?

I swapped the LSD carrier into a new diff housing and needed to swap the companion flange as well. As a result, I had to take the pinion nut off.

With the correct flange back on, I got the nut right back to where it was before on the shaft, but I wouldn't mind checking the backlash while I have the unit out.

Maybe I'll just have a look at the contact pattern using grease on the ring gear, and call it good if the pattern is all in the center and not biased to heel or toe.

IIRC, the torque spec for the companion flange nut is 134 lb-ft. If you are very experienced in this kind of thing, you can do it by feel. Checking with marker grease is a good idea.