I want a posi rear or possibly limited slip for my 92 RS. Where would be the best (and cheapest) place to find one? Would it be easier to go with a whole rear end swap? I don't know too much about these. thanks

 

what does posi mean?

 

A Posi & Limited Slip are the same thing. Check out www.slponline.com for there Limited Slip for $99.00.
You need to know your axle ratio for the correct application.

 

You also need to know what series your carrier is. If your running a stock 2.73 open diff, then I would segject upgrading the gears to either 3.42 or 3.73. If you upgrade you will want a 3 series posi unit, and if you dont, then your looking at a 2 series unit. Posi alone will help traction, but ****ty gears wont make you any faster.

 

Id definitely go with the SLP take out. Its a 3 series and you already have the required 28 spline axles. Find a set of used 3.42 or 3.73 gears and you'll be good to go. $120 for the posi after shipping, probably $100 for the gears, and $150 for the install.

 

I installed that Zexel torsen unit from SLP and so far I'm very happy with it. The 92 will already have the 28 spline axles, but in my 85 I had to convert to 28 spline. What's nice about the zexel is that it doesn't use clutches, so unless you overpower it and break it, it should last forever.

 

If you go with the slp unit you will have to get 3 series gears cause the ones u have now are 2 series. You might as well upgrade to 3.42's while your doing the posi.

Posi distibutes the power to both rear wheels while the open only goes to one.

 

The name Posi-Trac is GM's name for the Limited Slip rear which we all like to have. But sad to say this was a option most people at the time did not buy because of the expense. They are the same kind of common Limited slip.

 

i think your best bet would be to go with a whole rear-end swap its pretty easy to do the only think you might have problems with is getting the u bolts off there normally rusted on there really good but you can just cut em of and buy a new set if you need to. you should call around to the junk yards and see if they have any, im not sure where your from, but im from ohio and here we have a paper called the tradn post and people put alot of car parts and stuff in there for sale so my suggestion just check those places, good luck!

 

If JIM85IROC is correct about the splines, the swap is easy. Jim, I hope you're correct, I have a 92 and bought a Zexel unit from SLP and would like to install it without buying new axles.
I have done several carrier swaps, all you need to do is check the backlash before you pull the original out. The Zexel unit needs to be set to the same backlash and everything should be fine because the centerline of the carrier does not change so pinion depth is not an issue. Make sure you use a matched set of bearings and races, either the ones on the new carrier or your old ones. If you are going to replace the ring and pinion you should probably have the pinion depth checked so you get the correct shim. You can re-use the original shim and probably be ok, but I would measure to be sure. It beats ruining a new ring and pinion. If your current gear is below a 3:23 your ring gear will probably need a spacer to be used on the Zexel carrier. I think Zexels only came with 3:23 or higher so they only have one carrier size. Hope this helps.

 

I would just change the whole rear while you have the thing apart. That is if you have a stock axle in it. These are weak rears, and it will eventually go making you take it apart all over again. While you have it off change it to somtething fun, you gan get gears for 99 dollars, that are decent.

 

The cheapest way is the "Old Way", we used to weld all of the spider gears to the carrier(drop-out)and to each other. We never or rarely ever experienced axle breakage as some would have you believe. And we frequently brutally abused them at the track.
It will however wear the rear tires a little faster as it squeaks the inside tire on corners.
But I just bought a Zexel posi from "Randy's Ring&Pinion"($319), a worm gear limited slip unit with no clutches to wear out.(as stated before)But these "are" available at the junk yard on late model F-Bodies "If" the they don't ****** them for themselves.