how would i identify posi rear end?

 

look at the axle code on the door tag. I think anything that starts with a letter is a limited slip diff. Alternatively you can jack up the rear end and rotate a tire, if they both turn the same way it has some type of locking or limited slip diff. If they turn opposite ways it's an open diff.

 

You can always look at the metal tag attached to the stud on the differential.
If there is a 'L' in the middle of the ratio numbers then it is limited slip.
ie;
3L55 instead of 3.55, or 4L10 instead of 4.10 at the beginning of the series of numbers stamped on the tag.

 

i know H8 is limited slip 3.55 cause thats what i got got. you could always get stuck on purpose and see if both wheels are spinning other than that i believe all the suggestions have been said.

 

If you ain't stuck you ain't wheelin' hard enough!

 

All that code jazz will tell you what the truck originally came with, yes. But these trucks are old, and have usually been thru several owners. To make sure what you actually have under your truck, jack up the rear end and turn one wheel while observing the other. If the other wheel turns the same direction, you have a limited slip diff. If it turns in the opposite direction, then you have an open diff.

 

It's not like someone is going to swap carriers and put the old tag back on.
.....Doesn't mean the clutches are any good anymore.
But looking at the axle tag is a lot easier than jacking the rear up and counting revolutions to try and guesstimate the ratio.

 

True, putting the old tag back makes about as much sense as wipin' before you poop. But you do have to jack up the truck anyway and it would be a good idea to open it up and take a look inside.

 

I don't have to jack my truck up to do anything to the differential.
The tag is right there in plain sight.

In fact I changed out my driveshaft a few days ago with nothing but a chock.
It is on stock springs with no kind of lift at all.

 

My mistake. I was thinking I was posting in another thread about scrounging JY axles.