Hi guys. I have an excellent knowlege of my trans am and work on it a lot, but rear ends aren't my thing so I'm having my mechanic help me on this one. I've researched the site several times on this, but need to ask....

I'm swaping in an entire axle from (I believe) an 84 camaro with stock 3.73s, stock disk, and blown posi onto my 87 trans am with stock drum, 2.73s, and good posi. I plan to keep the 2.73 axle set aside in stock condition in case I blow up the other.

I've purchased a posi for a 3 series carrier (I hope, origins questionable) from an 89 camaro with 28 spline (spider?) gears. Both the soon-to-be-swapped 84 and the stock axle both have 26 spline

So my questions are can/should I replace the recently purchased posi's spline gear from 28 to 26, put it in the 84's rear end with the 3.73s and stock disk and be done with it or is that not possible or advised? Or would I be better off finding some used 28 spline axles with disk? I realized the 28 splines a little tougher, but I'm tired of collecting parts for this project. The posi spline gears seem to be buried in there but my mechanic says they can be changed. Or would you do something differently?

Clearly, my goal is to get 3.73s, and a posi into my car and paint the 84 axle with por-15, shocks etc etc etc. I'd like the disks too, though I realized they're not any better or possibly worse than the drum. Shoot me some ideas or ask questions if I didn't explain this right. I'm on a tight budget and thoughs about other types or rear end swaps are already realized, appreciated, but not what I'm asking for. Thanks a bunch guys!!!

 

The 10-bolt FAQ should answer most of your questions.

JamesC

 

Since they are both posi carriers you could probably swap out the spiders assuming it is the same style of carrier. Make sure you swap all the gears though. I wouldnt go mix and matching them.

 

Uh oh I handed the mechanic the posi I bought and he said it looked really different from the 84s. The guy I bought it from said it was a Torsen that came out of an 89 rear end. I should have mentioned that but I forgot about the name. Mechanic said he'd measure it and see if its going to fit in my 3 series...It is 28 spline.

Is this Torsen posi for my carrier or perhaps 4th gen camaro like a 95? According to my research a 4th gen posi swaps into a 3rd gen rear end, based on which size Torsen (T1 or T2) and what series the 3rd gen carrier is so I think I'm okay with the posi fitting but... now I gotta find 28 spline axles preferably with disk for a 3rd gen carrier...that sounds like a tough find...And wouldn't any stock 28 spline axle especially from a 4th gen be too long for my old 84 carrier unless I buy aftermarket ones from summit for like $250?

Thank god I only paid $50 for this Torsen posi and got 3.42s thrown in with it. Let me know what you think I should do. Will try to get some pictures posted soon...the Torsen pics I've seen online look like the one I bought so that answers that...

 

The 84 probably has a Gov-Loc; the 89 should be an Auburn. Pics and info in the link I mention (sticky at the top of the page), if you care to look.

JamesC

 

Hi James and thanks very much. I know its hard to tolerate noobs like me. I've read that sticky about 25 times but, having never opened up a rear end, much less done work on one, its a little greek to me. Sorry if my questions are less than intelligent!

Whatever the posi is in the 84 is blown. Thats a certainty. The posi I bought is definetly a Torsen, it looks like the ones I've seen and doesn't look at all like the Auburn and doesn't have visible yellow springs.

I think my question is down to the 28 spline axles that I'll need for this Torsen posi that I believe will fit into my 84 carrier. I think the only ones that will fit would come from a 90-92 3rd gen, and will be d*** hard to find, so I probably should sell this Torsen posi and rethink this, or cough up the $250 from Summit for the right axles..... Is that about right?

 

Personally, I wouldn't purchase used axles, but if you decide to go that route, the 28-spline axles from a 90-92 will fit (take note from the FAQ that either drum or disc will work, but the drum flange will have to be turned down). I purchased new from Summit.

BTW, we were all noobs at some point .

JamesC

 

My mechanic just told me that the posi does seem to fit into the carrier but that the stock 3.73 gears that are in that 84 carrier are too thick. He mentioned something about an extra tooth... I guess possibly this torsen posi is for a 2 series carrier since that 84 has to be a 3 series with that gear ratio. Right?

Guess I'm going to take a step back and sell the whole thing this is getting ridiculous...

 

There are companies that make THICKER aftermarket gears to bolt 3 series gears onto 2 series posi units. If you can't find those, they make ring gear spacers to achieve the same result with stock GM gears.

If I were you, i'd sell all that misc. junk you have, and buy the 30 dollar spacer/longer bolt kit.