Ok this is probably going to be a dumb question but here goes... I am doing a turbo swap in my base 87 and have decided to keep the n/a rear end from lack of being able to find a TII rear end ANYWHERE. So aside from buying the custom drive shaft from mazdatrix i also need the lsd, correct?

 

I'm not sure what the question is exactly. If you want know know if you should use an NA LSD instead of an NA open diff, the answer is yes.

 

is that fairly simple?

 

NA rear ends are interchangeable. You need to drop the rear subframe to change one out.

 

Necro thread!!

This is false, btw. I literally just came inside from pulling the rear end out of my 86 GXL and never even thought about pulling the subframe off.

What I DIDN'T think about until I had finished the job, was whether or not the S4 and the S5 differentials bolted up the same way? Like, can I use this 86 LSD differential on my 90 GTU?

 

It's not false at all. You either loosen the nuts holding the subframe up, and drop it partially, or you drop the whole thing down. I've done both. If you leave it, you're making the job harder than it needs to be. The nuts on the front diff mount can be a pain in the ***, and giving yourself more room to work is in your best interest.

All NA diffs are interchangeable. Same bolt patterns and same mounting.

 

Not when you literally don't have the ability to take down the subframe. When you're working on Autozone jacks in a gravel driveway, sometimes it's easier to leave things be. And I literally didn't have any problem with the front diff mount bolts at all.

Cool. So my driveshaft should fit right up to it? I remember some other issue I had where the S4 and S5 center bores were different, and I couldn't make my S4 parts work. I cannot recall what it was I was trying to do though...

 

You're lucky. My front mount took about an hour to take out, and that was with an extra ~3" from the frame being dropped down. Gravel sounds like fun; I think I'd be wondering how long before the car fell on my head.

 

You do what you gotta do. Lol. There was that one moment when the pinch weld folded and the car shifted suddenly that I had to catch my breath, LOL!

 

I too have to work on gravel. I'm always terrified under the car haha.

I'm skinny enough to squeeze between the car and the ground, but it's a pain to work like that.

 

i have an 86 na base will the TII rear swap over without an issue cause im plaining on going turbo just wanna make sure