Ok Im wondering here how doable it is for me to do these mods on limited budget. Been talking to mechanics and people and doing as much research on the net as possible, truth be told I have never done many mods but am very interested in cars and performance. One of the things I really want to do is switch my 91 camaro 305 tbi with 2.73 gears to posi with 3.42 gears and have speedometer read correctly. To do this entire job, what am I looking at for time and pricing, figuring I'll get the parts myself.

Mechanics say the aftermarket posi's aren't usually as good as the factory or aren't that great at all. Is this true? Was thinking of getting the 100 dollar SLP posi, is it any good? http://www.slponline.com/view_produc...TNUMBER=64501T
Can someone explain to me what carrier three is? How can I tell if gears or posi I order are carrier 3? I know I will need a gear install kit for the job, does this contain everything needed? What other parts would be needed for the entire job? One mechanic said 8 hours labor *but he was kinda guessing*...what hours am I looking at shop time? Has anyone done these mods/had a shop do them, what kinda hours did it take? ALso what's needed to make speedometer read right? Will any computer related things need changing or anything with the tranny? Lots of questions I know, but could use a lot of info and the search function still isn't working!! Any further info is also appreciated...Thanks in advance to any patient enough for this post

 

Aftermarket posi units are often vastly superior to factory ones. Some of the factory ones (especially the ones they put in S-10s) are pure crap.

The SLP one is a pretty decent one. They take (took) those out of LS1 cars and put in a heavier-duty version of it when they built the SSs.

Besides the "gear kit" you'll need some fluid; axle bearings are a great idea, since they only add about 5 minutes and $20 to the job; I prefer to use a "crush sleeve eliminator" aka "solid pinion spacer" rather than a crush sleeve; not too much else.

To make the speedo right you'll need the right gears for it. Those only come from the dealer and I hear they're getting hard to find for the better ratios.

If you use the SLP posi, it's a 3-series carrier, so normal everyday non-special 3.42 or 3.73 gears will fit it.

It takes me about 4- 4½ hours to do a gear swap in my garage but I'm not very good at it. Shop time for an experienced person to do it on a rack is around 3 hours.

 

Thanks a bunch for the info! By the way, love your sig

 

I just went through the exact mod your talking about w/ the same car.

I went w/a Eaton because I found a price on ebay for it that was as cheap as an auburn or anything else out there that was brand new. I bought Eaton part no. 19599-010. You can check out your options at Eatons web site: http://www.traction.eaton.com/prod5.htm
But I think this is the only posi that'll work with a stock 91 camaro.
I got my 3.23 gears from Jegs.

OK so now you got a carrier and the gears. Thats the most expensive part.
NOw you need some tools and other stuff.
Tools:
1) Pinion Depth checker = $100 at Summit
2) Dial Indicator: You get one with the Pinion depth checker ($0)
3) Dial indicator stand: $50
4) Bearing Separator: $55 from Grainger (Grainger.com or if you have a local store)
5) Hydraulic Press: $60, or if you make one like I did w/a welder probably about $30
6) Impact wrench: $150 for a nice one w/ atleast $200ft.lbs.
Note: You need item 4 so you can remove the old bearing from the pinion gear to get at the pinion shim (you must reuse the old pinion shim on the new pinion). You need item 5 so you can press new bearings on the Posi and the new pinion gear. If you want you can have a shop do all this pressing and pulling for probably
less than $30, but you might have to make several trips to the shop if you have to adjust the pinion shim thickness. And if you do buy these tools it's free in the future to change your gears. A hydraulic press is good for other stuff too. I happened to wreck my U-joint taking it out and used the press to put in the new U-joint.

Now you need the parts. The main parts you need are:
1) 2 new carrier bearings
2) Carrier shims kit, possibly pinion shims (I didn't need them)
3) New gasket for the cover
4) New Crush Sleeve
5) New Pinion nut
6) Marking compound for contact pattern
7) Limited Slip additive = $5
8) The right gear oil = $5

For items 1,2,3,4,5,6 your best bet is a kit from summit or jegs: about $100

That's all you need. For instructions I would say go to f-body.org. There is a nice
tech article there. Or do a search on the internet - tons of good stuff.

Bottom line: Don't let the job intimidate you. Do it right and it WILL work. It did for me. And you'll also learn something. Good luck man!

 

OR.... the lazy (and leat expensive) route - get a complete rear end from local yard with the posi and gears you want, and swap the whole rear end. I just did mine 2 weeks ago, went from 2.73 peg leg to 3.08 posi - took me a Saturday, and cost me $250 total, including lubes, posi additive, bearings, complete new brake parts, new coil springs, new shocks, and poly sway bar bushings.

Wasn't the 3.42's I wanted, but the complete drum-to-drum rear only cost me $125 - so I settled for now. Someday I'll find another used rear with 3.42's for $125 and I'll do it all again

 

I did this yesterday on my 92 Z28. I work at a shop, so I did mine on a rack, which makes it so much easier. It took about 3 hours or so. When you do your swap, REUSE ALL THE FACOTRY SHIMS, because usually they are the correct shims for the new gear too. This means you wont have to reset the pinion depth which is always nice.
Installing a new posi doesnt add to the overall time of the job, since the old carrier has to come out anyway. Actually, in my case it was faster because I didn't have to unbolt the old ring gear from the carrier. I just bolted the new ring gear to the new carrier, and I was in business.
And to answer your question about carrier series, here's the deal:

Factory gears that are neumarically lower that a 3:1 ratio use a series 2 carier. I.E. 2.77

Factory gears that are neumarically higher that a 3:1 ratio use a series 3 carier. I.E. 3.42

If you're buying a new posi AND a new gear, just order both in the same series, since gears come in series 2 and 3 also.