Transmissions and DrivetrainNeed help with your trans? Problems with your axle?
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since i got ripped off on a rearend last friday, i was wondering i got a junkyard down the road who has a late 80's early 90's firebird with the v6 its got the big ground efffect kit on it. I was wondering if the rearend is better then mine is a 2:73 standard. And is the one im looking at posi from a stock standpoint i will be sure to test it anyways. if its standard non posi is it better then the one i got tho??
What do you have now? The 7.5 10 bolt got 28 spline axles in '90, so if it's a '90 or later then it will have the big axles. You will have to remove the cover to see what is in it.
Being in a V6 car, if the V6 has a manual trans, it could be a 3.08:1 gear, if the trans is the version with the 4.03:1 first gear. There's no EASY way to determine that, so hope it has an automatic, in which case it should be 3.42:1. NONE of the V6 versions came with a posi. If it's a '90-'92, it should have the 28-spline axles. Otherwise, it's probably 26 spline. Either way, it should be a 7.625" ring gear.
ok yeah its a automatic im looking at a item on ebay right now i got a spare rearend unmolested with 2:73 gears will my old spider gears work for this Specsulled from a 86 camaro Z28 posi carrier with 3.08 gears or 13:40 26 spline 7 5/8 this is a auburn carrier looks to be in great shape. http://cgi.ebay.com/ebaymotors/82-92...Q5fAccessories
An Auburn can look brand new on the outside and be completely worn out on the inside. An Auburn can not be rebuilt, so if it's worn out, it's scrap metal.
Thanks gear head and others,"i've managed to put new motor trans in on my own from forums online i got no friends automobile illeterate like myself i just do my best.
im glad you know what your talking about it can save me a headache, im just trying to get somethign posi going with my motor in my car it has issues with the trans and rear end setup i'd say i prob got 280-300 rear wheel horsepower. It spins to easy like just taking off trying to pull out somewhere real quick but not like scary fast, right wheel spins out the ace. Since the 700r4 doesnt have the plug for the overdrive im riding solo 3 gears, for now bc my wiring was killed when i got the car, i thought maybe a posi rearend would fix the problem and make it grab i weled the spider gears on it and broke the rearend already lol.
If you welded it and it broke then you are lucky that the axles didn't come out. This can be very dangerous. I recommend a new Eaton Posi. It's my opinion that the Eaton is the best street/strip differential for most GM performance cars. It can be tuned to fit your needs, it can be rebuilt if it ever wears out and it will last much longer than the Auburn and most other differentials.
Yea, those are cheap, but also not very strong. I have removed the governor before and added clutches and preload springs to make them work like the Eaton Posi, but the case is still weak.
Yea, those are cheap, but also not very strong. I have removed the governor before and added clutches and preload springs to make them work like the Eaton Posi, but the case is still weak.
So how can you tell the quality of the case/unit? I'm new to the Eaton/Auburn/Torsen differential debate. Where is a good place to buy a quality piece from?
In my opinion there are no good Auburn units. I quit selling them many years ago because of problems that my customers were having. I got tired of scraping all of that metal sludge out of the hosuing when I had to replace them. The Eaton is just a much better unit. It will cost more, but it's well worth the money. I don't have any experience with the Torsen, but I know that they do well in auto cross and road racing. Some people have had slight problems with th eTruetrac when drag racing. Seems that they don't want to lock up sometimes. The Torsen and Truetrac are similar in design. biggearhead@bellsouth.net
if you swap in an eaton or a torsen to the 3.42 axle, then you have to get the backlash exactly where it was, and that can prove difficult to impossible. Instead consider a conversion-style locker like the PowerTrax. These are stronger than the ring gear, so the ring gear remains the weakest link. These are also cheaper than an Eaton. Best of all, no messing with backlash!
In my opinion there are no good Auburn units. I quit selling them many years ago because of problems that my customers were having. I got tired of scraping all of that metal sludge out of the hosuing when I had to replace them. The Eaton is just a much better unit. It will cost more, but it's well worth the money. I don't have any experience with the Torsen, but I know that they do well in auto cross and road racing. Some people have had slight problems with th eTruetrac when drag racing. Seems that they don't want to lock up sometimes. The Torsen and Truetrac are similar in design. biggearhead@bellsouth.net
Oh, you were talking about the Auburn unit case. I thought you were refering to the Eaton unit in the ebay link above.
if you swap in an eaton or a torsen to the 3.42 axle, then you have to get the backlash exactly where it was, and that can prove difficult to impossible. Instead consider a conversion-style locker like the PowerTrax. These are stronger than the ring gear, so the ring gear remains the weakest link. These are also cheaper than an Eaton. Best of all, no messing with backlash!
Stay FAR FAR away from the Powertrash unit. Backlash isn't that hard to set if you have the proper tools. I put a Powertrax unit in years ago just so I didn't have to disturb the backlash. They jerk, bang, and make all sorts of loud noises. Great for all out drag racing or 4-wheeling, but miserable in a street driven car. I changed an open carrier in a 3.42 geared 10 bolt for a Torsen unit last year, re-used the same carrier shims, and the backlash came out at a perfect .006". The only shimming that was a little complicated was on the pinion since I replaced the crush sleeve with a solid spacer. Even if the backlash doesn't come out perfect with the old shims, all you have to do is buy a set of carrier super shims and have a dial indicator/magnetic base handy, and you can have the backlash deadnuts pretty quick. A cheap $20 digital caliper from Harbor Freight is handy for measuring shims. I hated that Powertrax so bad I actually took it back out and ran a plain old open carrier until I saved up the money to put an Eaton clutch style posi in.
__________________ 89RS w/350 TPI; 69RS/SS w/450 HP 350/Muncie 4-Speed "Too weird to live, too rare to die."
ulled from a 86 camaro Z28 posi carrier with 3.08 gears or 13:40 26 spline 7 5/8 this is a auburn carrier looks to be in great shape. 
Stay FAR FAR away from the Powertrash unit. Backlash isn't that hard to set if you have the proper tools. I put a Powertrax unit in years ago just so I didn't have to disturb the backlash. They jerk, bang, and make all sorts of loud noises. Great for all out drag racing or 4-wheeling, but miserable in a street driven car. I changed an open carrier in a 3.42 geared 10 bolt for a Torsen unit last year, re-used the same carrier shims, and the backlash came out at a perfect .006". The only shimming that was a little complicated was on the pinion since I replaced the crush sleeve with a solid spacer. Even if the backlash doesn't come out perfect with the old shims, all you have to do is buy a set of carrier super shims and have a dial indicator/magnetic base handy, and you can have the backlash deadnuts pretty quick. A cheap $20 digital caliper from Harbor Freight is handy for measuring shims. I hated that Powertrax so bad I actually took it back out and ran a plain old open carrier until I saved up the money to put an Eaton clutch style posi in. 
