I did some searching and I'm pretty sure this will work, but want check with you guys to be certain. I currently have a 90 N/A with an open diff. Found this add for an 86 diff: http://www.usedregina.com/classified-ad/8922935 and want to make sure:

1. Is it an LSD? which from my searching I found this "spin one axle. if the other axle spins backwards, its not an LSD. if it spins the same way, its an LSD." So that's what i will do...

2. What should I look for to make sure it's in good shape?

3. Do I need the half shafts and a drive shaft, or can I use the ones i have?

 

If it really came from a GXL, it is an LSD.

 

I have a '90 GXL with an open diff. You better make certain before purchasing.

 

S4 (86-88) GXLs had LSD; S5 (89-91) did not.

 

it will have a TAG on the Filler nut,that Reads "use Limited slip differential Oil Only!".(seriously..a tag.).

 

Thanks guys, i went and looked at it in person and it is an LSD... So now my other question is will an s4 LSD be and direct swap?

 

Yeah, it's a direct swap with any NA diff.

 

Sweet, thanks! I'm gonna go buy it today!

 

Certain miata LSD's also fit. I can't remember which years work but it's on here somewhere. It's a helical type instead of clutch type. That's what I did.

 

Yes,but doesn't that involve taking the Rear end apart and swapping Parts?
I believe the poster is just Wanting to Remove his open end diff and replace it with a LSD.
Those 2 are swappable.Also,If you are getting under the car to do that,you may want to think about a Camber adjuster(for bigger wheels).It never hurts to think about Putting stuff on when you are in the Same"vicinity".Why jack up the car more than you have to Right??
I'm swapping a N/A LSD for the TII LSD and shafts,driveshaft,etc.I am putting in my Camber adjuster while I am there.Also,while the car is "down"I am throwing in my Walbro pump.
Anyways good Luck to ya.I am sure if you run into anything,Just POST up and the Guys here are more than willing to help ya out.Cheers,STYX!~

 

All I did was get the LSD only, took the differential out and took it to Pineapple racing and had them take the open one out and put the limited slip in. Didn't have to change anything else.