Posi-rear question...

[Mirth]

Hey guys, I just bought a 1996 Mustang GT Conv. I'm not that auto-savy, so that's why I've come here with my question.

While I was going to take the tires off to rotate them while on the stands, I noticed when I spun one of the rear tires, the one on the other side went in the opposite direction. I thought with a posi-rear that they were supposed to go in the same direction?

Also, one of the back tires had a ton of tread on it, while one of them had a lot of wear.

Not too sure how posi-rear works, but could this mean that only one of the wheels is being driven? I noticed that the rear-end has yellow chalked numbers on it, like it probably was one that came from a junkyard.

Any info would be greatly appreciated. Sorry if this is a stupid question.

 

[wmburns]

A Ford Mustang 8.8 is an LSD (limited slip diff). It is different from a POSI but does the same thing. Quite possible that someone has replaced your diff with an open diff.

There is a metal tag attached the the diff case. There are codes for the ratio and configuration. If the code is "3.27", it is an open 3.27. If it is "3L27", then it is a limited slip. Of course this assumes someone didn't swap the tags.

Also suggest confirming the ring gear size. I have heard of cases where the V6 rear end was installed on a GT.

 

[trinity_gt]

I have heard of cases where the V6 rear end was installed on a GT.

Was thinking the same thing: With the yellow ink on the housing it definitely sounds like a junk-yard replacement and it's very possible it's from a V6.

Mirth, get the tag info first. If you can, snap a pic of the rear. Sometimes you might be able to tell from outward appearances. For example, I found one comparison:

7.5" V6 rear cover:
View attachment 227999

8.8" V8 rear cover:
View attachment 228000

And from another site:

View attachment 228001

When you rotated the one wheel (a) was the transmission in neutral and (b) did the other rotate freely or did it require any force? Perhaps you've got a TLok but it's simply toast...