I'm making out my junkyard shopping list. I will be going to a very big, cheap priced junkyard the weekend of jan. 18.

I wanted to check with yall to see if GM used a code on the list on the consol lid, any other placed or stamped code on the axle tubes to tell what gear ratio the car had and if its open or posi. If GM used the codes on the third gen f-bodys, do any of yall know where I can find the list?

I got an open 3.42 in mine now, and wanted to keep atleast a 3.42 or lower gear like 3.55, 3.73, but I want to pull a used posi unit, carrier, gear set all as one unit so I won't have to worry about setting of the ring gear
Thanks
John

 

There's 3 good places to look that I know of. First, there MAY be a tag on the rear diff cover saying to use Limited Slip additive or something like that. My posi 9 bolts have them. Second, there's usually a stamped 3 letter/number code on the passenger side axle tube facing the front of the car. My old '83 Z had this, my '88 Iroc does not (or I can't find it). I can't remember what they mean but they're listed in a Haynes manual for the '82-'92 Camaro/Firebirds. Third, IF there's an RPO code sheet still in the glove box in the console, it'll have a G80, denoting -AXLE POSITRACTION, LIMITED SLIP

HTH...Ed

 

You can't re-use the gears. The "setup" doesn't have to do with the gears, the variable is the housing. Consider the shims to be part of the housing, making the housing match a standard dimension, rather than part of the gears. If you move parts to a different housing, you can't use the shims that came with the parts (gears or carrier). You can take a carrier and stick it in a different housing, and re-use the housing's shims, about 99% of the time.

All you need to find is a posi carrier with the same spline count as yours, either 88-back 26-spline, or 90-up 28-spline, and 3-series to match your 3-series gears. Good luck. Look for a 305 TPI 5-speed car, or a 350 TPI automatic car with the optional ratio, I doubt seriously that anything else will have it.

If you don't score at the buzzard, go here http://www.slponline.com/view_produc...TNUMBER=64501T if you have a 90-up car. This fits 28-spline axles.

 

Thank's guys..

If I find one I might just grab the whole rear, housing and all, bening the price at this yard is only $64 for any whole rear (no counting any brake parts)

 

Why dont you just turn the wheels? If its a posi, they will turn the same direction, if its an open...they wont. If you find what you think may be a posi, pop the cover off and look at the stampings on the gears to figure out the ratio. That is of course if there arent any tags bolted to the cover. A good place to find good gears is in S-10 pickups or Astro vans. Most of these use the 7.5" rear, like most f-cars. Normally you can find a set of 3.42's or 3.73's. I got my 3.73's a while back out of my 86 V-6 S-10. Hope this helps.