I need a posi rear end and I don't even know where to start. Any one upgrade their rear end to posi before? Any tips?

I need to get these one wheel peel days out of my life, especially at the track..

 

Cheapest easiest fix is a 4th gen rear end. You can find them with posi, better gearing (right now you are 2.73), and get the rear disc brakes. It's pretty easy to get one with 3.42 rear gears and posi, these days maybe $250? (I got mine 4 years ago for $180 so I'm guessing here). They are a direct swap, easy to do in the driveway.

Possible issues:
1) rear stock wheels will stick out about 1 1/2 inches farther each side of car - 4th gens had longer axles and more backspacing on their rims.
2) If you have 15 in wheels now, LS1 (1998 - 2002) rear disc brakes won't fit in them, don't know about the LT1 discs(1993 - 1997)
3) E-brake lines won't match - have to do some rigging here to make ebrakes works
4) different rear gears means speedo will be off, and you'll need new speedo gears for the tranny to have an accurate speedo - not hard to do, and needed regardless if you change rear gears
5) proportioning valve - some swap out for a proportioning valve for a 3rd gen rear disc car to make sure the right amount of fluid pressure goes to the rear disc brakes, others say they just left it as was and all was fine - I think technically the rear disc brakes require less fluid pressure than the drums did, and thus the swap to the different proportioning valve. I played it safe and swapped my prop valve, but others say it's fine with the stock valve.

Otherwise, you'll have to get a posi unit for your axles and carrier (you should have 28 spline axles I think), and have a shop install it maybe? I know there's somethings you need special tools for when working on the differentials, not sure if this is one of them - there's preloading and clearancing and all kinds of wonderful stuff that's over my head!

 

Start with the following FAQ:

https://www.thirdgen.org/forums/tran...-10-bolts.html

JamesC

 

If you have 3.23, 3.42 or 3.73 gears then I recommend installing a new Eaton Posi. Here is how it's done. http://www.nastyz28.com/forum/showthread.php?t=19773 A new Eaton is $440 and you will need bearings and shims to install it. They are about $45.

 

https://www.thirdgen.org/forums/tran...questions.html


Honestly it would be easier and probably cheaper to get a used rear that already has a limited slip or locker than it would be to put one into an open rear.

 

I too would just get a 4th gen rear. No offense to the OP but if he doesnt even know where to start as far as getting a limited slip diff, then he doesnt know enough to install gears. At least not properly

 

Just get a powertrax no slip locker. You can put it in, in your drive way in about an hour or two.

 

The locker would be great for drag racing and limited street use. I know the no slip locker allows the diff to open for turning and does so better then the old school lockers but for everyday use it still isn't as smooth as the limited slip. For a daily driver limited slip is the way to go.

 

10 Bolt upgrade photos
Just some photos of my 10 bolt upgrade including a Eaton 28 spline posi, new 28 spline axles ,3.42 ring and pinion and LPW Ultimate cover. Here's a link to the Eaton posi unit. = http://www.eaton.com/EatonCom/Produc...iteId=EatonCom and here's a link for the LPW cover.= http://www.lpwracing.com/p_capcovers.asp You must scroll down the page to see the 10 bolt cover.

$700.00 for axles and installation parts and labor including 3.42 ring and pinion ,$535.00 Eaton Posi.,$169.00 LPW Ultimate support cover.. 3 year warranty. Total = $1,404.00.

 

Two more photos. All done at " The Rear End Shop" All they do is rear end work for over the last 20 years.
If your happy with your gear ratio (I strongly recommend upgrading to a 3.42 while your in there.) and already have 28 spline axles all you will need is the Eaton posi. and someone to put it in. The covers just a bonus. If your taking it to the track than a support cover can help a 10 bolt greatly.