LSD question?
 

I have an '86 base with a non-limited slip diff that has bearing howl. I found a good limited slip diff at a wrecking yard.(Its just the center section/pumpkin) I thought it was a direct bolt in but I hear now that the TurboIIs are different.
How do I tell just by looking at the pumpkin/center section if its out of a NA or a turbo? What are the differences? Is there something on the outside of my non-LSD diff that I can compare to the LSD without having to take the one in the car out?

if its a turbo car then its probably a TII LSD if it is an N/a then it is probably an N/a LSD

Yes, but does it say it on the LSD center section/pumpkin somewhere? I don't know what kind of car it came out of.

if you don't know what kind of car it came out how do you know if its an FC rear in the first place?

If you didn't see the car that it came from, and din't pull it yourself, I wouldn't use it unless you can first confirm that it is indeed an FC rear end. It would suck to try and boltup a Ford 7.5 or something.

I got it from a wrecking yard that specializes in Mazdas. I know the general look of the RX7 rear end and there were a bunch of them togather, some non-LSDs with the mounts.
What I don't know is what is the exact difference between the non-LSD, NA LSD and Turbo LSD. Are they all interchangeable? I've heard that the Turbo LSD is different than the NA non-LSD and LSD

The Turbo LSD is complete different physically. It is an 8 inch rear end, so it is much larger.

I work in Port Orchard.. I think I know wich Mazda wrecking yard you're talking about if its the one in Troutdale or Sandy, OR. They should be able to help you. I wish I had the parts book, it would have the part numbers. Maybe call Mazda and ask them if they have the part number for the T2 LSD, and NA LSD. If no one has an answer by tomorrow, I'll read the numbers off my '88 GXL LSD and give you that... process of elimination :D

Thanks! Its the Covey's wrecking yard in Marysville, Wa.
I'm going to give them a call, but if they can't tell me what model car it came out of I'll probible just take it back and get a non-LSD one.

Why dont you just open it up and look if you aren't sure? Its only a few (10 I think..) 12mm bolts that go around the diameter of the diff. Just pull the stub axles out, take all the bolts off, and pull the diff apart. It will take all of 10minutes tops. If you dont know what you are looking at, post a picture or describe it and we can tell you.

*edit*- Here is a write-up I did while swapping a torsen LSD into my Rx-7 diff.

https://www.rx7club.com/forum/showth...hreadid=218048

Look at the 1st two pictures. The first one you can see all of the 12mm bolts that you will need to remove. then once you seperate it, the second pic is what you will be looking at. If you can see 2 big gears in that section, those are the spider gears and it is an open diff. If it is enclosed for the most part, then it is a limited slip unit. (will be able to see in a few slots, but not huge and open like the open diff is..) If it is a LSD, and you arent sure if its a T2 or N/A, measure the ring gear diameter. If it is 7", its a N/A, and if it is 8", its a turbo. YOu will not want to unbolt anything further, or take the LSD unit out, as you will then need to re-adjust backlash and a few other things.

Thanks! As I said in one of my first posts, all I have is the center section/pumpkin sitting on my work bench. I did measure the ring and it looks like 8" so its a turbo diff and back to the wrecking yard it goes.

The flanges for the driveshaft and halfshafts are larger on the t2 unit.

I took the LSD back to the wrecking yard and got a non-LSD. The didn't have a GXL LSD in stock. All the LSDs they had were from TurboIIs