Rebuild posi or ...

[JerzyIroc]

My rear has a 2.73 Posi in it. However, now its a one legger. I"m sure the clutches on the posi unit are bad. I cant afford to go all out and build a crazy rear, but i would like to at least get them both spinning again. So is it worth rebuilding the posi unit and putting 3.xx while im at it? Or should i just buy a complete stock posi rear from somewhere for like 300 bucks? If i were to go the rebuild route how much harder is it to rebuild than a non posi unit??

[wretched73]

Well i dont know a whole lot, but if you do put different gears in put the summit ones in. They are about $100 cheaper and are made of the same steel as richmond etc....

[deadtrend1]

I always preferred motive gears.

what year is the rear. help determine 26 or 28 spline.

[JerzyIroc]

Its an 87 iroc. G80 code. says 2.73 posi. No idea on the spline. what do you guys think? Just rebuild the posi and throw some 3.43 or something? how much could that cost? def yes on the summit gears. ive heard that from quite a few people

[IROCdan330]

G80 is the rpo for a posi rear axle.

GU2 is for 2.73s, you sure thats what you got?

If it is, and you want to upgrade to 3.xx gears, I do believe you will need a new carrier unit with the gears, not just gears.

honestly it would probably be cheaper to get another rear with the desired gears.

[Tru2Chevy]

Originally Posted by IROCdan330

If it is, and you want to upgrade to 3.xx gears, I do believe you will need a new carrier unit with the gears, not just gears.

You can buy 3.42/3.73/4.10 gears for a 10 bolt with a 2 series carrier (which is for 3.08 and taller gears)....

- Justin

[IROCdan330]

thanks for the update Justin, I didnt know that.

[JerzyIroc]

I downloaded the RPO decoder from TGO. On my RPO tag is has GU2 and G80 right next to it. So i got a 2.73 posi. How much would it be to rebuild the posi and get some 3.73's? Or would i be better off just getting a stock one like dan suggested?

[IROCdan330]

Hit up Josh over at JS Performance : 215 783 4645

He will be able to quote you an awesome deal on a gear install and help you with whatever decisions you need to make ie rebuilding the rear or getting a new one, gear selection, etc...

[WildBillyT]

Originally Posted by JerzyIroc

I downloaded the RPO decoder from TGO. On my RPO tag is has GU2 and G80 right next to it. So i got a 2.73 posi. How much would it be to rebuild the posi and get some 3.73's? Or would i be better off just getting a stock one like dan suggested?

Rebuilding a clutch style posi is not too difficult, and shouldn't be too expensive as long as it's in rebuildable shape. As Justin said, you can then get thicker gears for use w/ a 2 series carrier.

[JerzyIroc]

you can then get thicker gears for use w/ a 2 series carrier.

[WildBillyT]

Originally Posted by JerzyIroc

you can then get thicker gears for use w/ a 2 series carrier.

http://www.jegs.com/p/Richmond+Gear/...10002/-1/10167

Check out the 10-Bolt 7.5'' & 7.625'' section. You will note that they list gearsets for both 2 and 3 series carriers.

Back when they only made one type of gear set for each rear type (regardless of carrier) you had to use a spacer to use the 3-series gears on a 2-series carrier. Using spacers is not really a good idea so Richmond and some others decided to manufacture their gears "thicker"- or, in other words, "build the spacer right into the gears" so that you don't have to use one.

The reason for this extra "space" that needs to be taken up is because of the thickness of the ring gear flange on the carrier. Lower numerical gearsets have more teeth on the pinion gear so it's larger, and the ring gear has to move out to make up for this extra size. On 2 series carriers the flange is thinner to allow for this. Higher numerical gearsets have a smaller pinion so the ring gear has to be closer to the pinion, and the flange is thicker. The difference between the flanges is how big the spacer or extra material on the ring gear is.

[JerzyIroc]

ahh ok. the thought of putting a 4th gen crossed my mine. but im sure they dont just bolt in. how much do those go for and what kinda bs would i be looking at to swap a 4th gen rear?

[Tru2Chevy]

A 4th gen rear will bolt right into a 3rd gen, no problems. They are ~2" wider on each side, so you would have to run rear wheels that are sized to fit a 4th gen.

- Justin

[IROCdan330]

Don't forget about brakes. If you have a drum rear currently in the car and get a 4th gen w/ discs, you would need to install an adjustable proportioning valve which isn't a hard task...I believe the e-brake cables are different as well, to take up for the 2" difference on each side. I know I had to change mine, as well as the routing location underneath the car.

4th gen rears go anywhere from $200-400.

Edit: You can run 3rd gen wheels, it just won't sit as it did before, it would have more of a bulldog stance...and if there is enough body roll and you don't roll the fender lip, it can bump the tire a bit. 4th gen backspacing as Justin said would correct that.

[JerzyIroc]

So if i were to put a 4th gen (ls1 not lt1) driveshaft and rear it would just bolt in? no modifications at all except the brakes? mine is an auto, would i be able to use the same torque arm or would i have to get a special one?

[Tru2Chevy]

Originally Posted by JerzyIroc

So if i were to put a 4th gen (ls1 not lt1) driveshaft and rear it would just bolt in? no modifications at all except the brakes? mine is an auto, would i be able to use the same torque arm or would i have to get a special one?

The rear would fit fine, and all of your suspension parts will bolt right up to it with no issues. The only issue you would have is brakes (if you have rear drums now) and wheels (as mentioned above).

- Justin

[JerzyIroc]

sweetness.