Transmissions and DrivetrainNeed help with your trans? Problems with your axle?
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im rebuilding the whole car over winter (90 Iroc stock) and im looking at around 300 hp and maybe a basic NOS set up
now are they stock a 9 bolt? what would be a good way to go about this, can i just buy a new differential unit from like Auburn ect and use it in the same housing? or would i have to get a whole new *** end?
any other input or ideas would be great thanks!
p.s. its going to be my DD but ill be at the strip once in a while
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Do you have a 9 bolt? If you do then you are limited to the Borg Warner differential. Auburn, Eaton and none of the other manufacturers make a differential for the 9 bolt. In stock form the 9 bolt is a pretty good rear end for 300 HP.
If you have a 10 bolt then you have more options. You could get an Auburn for it, but I don't recommend it. It's my opinion that the Auburn is junk. The Eaton Posi is a much better differential. You could also get a T/A Performance aluminum support cover for the 10 bolt or the 9 bolt. This will help strengthen the housing and make the gears last longer.
I believe they stopped 9 bolts around 87. Count number of bolts on center housing, you should have 10. Also I think 90-92 cars came with 28 spline axles versus 26 for others. They make aftermarket axles that are supposed to be 35% stronger than stock. I believe stock 28 spline is fine for most 350 builds. Problem with 10 bolt is smaller housing at 7.65 inches. Torque twisting the housing is what kills gears inside.
Biggest help would be aluminum differential cover, transmission torque arm and subframe connectors. You can upgrade axles if you want. Check out below links. There might be some internals that you can upgrade too like zytanium crosspin. Your car came with decent gears that should work well with your build. I would keep gears but beef up what you can. Full aftermarket axle that bolts in like Dana S60 or Moser 10 bolt will be $2,500. I don't know if SLP still sells a torsen differential as mentioned in links.
I believe they stopped 9 bolts around 87. Count number of bolts on center housing, you should have 10. Also I think 90-92 cars came with 28 spline axles versus 26 for others. They make aftermarket axles that are supposed to be 35% stronger than stock. I believe stock 28 spline is fine for most 350 builds. Problem with 10 bolt is smaller housing at 7.65 inches. Torque twisting the housing is what kills gears inside.
Biggest help would be aluminum differential cover, transmission torque arm and subframe connectors. You can upgrade axles if you want. Check out below links. There might be some internals that you can upgrade too like zytanium crosspin. Your car came with decent gears that should work well with your build. I would keep gears but beef up what you can. Full aftermarket axle that bolts in like Dana S60 or Moser 10 bolt will be $2,500. I don't know if SLP still sells a torsen differential as mentioned in links.
Maybe somebody else know this, but is there a reason to rebuild or replace your stock posi unit? New detroit diff is $410, detriot locking diff is $540 and eaton posi is $520.
If you decided on aftermarket axles, stay away from american alloy. I've read on this site that people have had problems installing C clip on them. I would order set from Moser.
I like the Eaton Posi best. I've had less trouble with them than any others. I haven't installed any Truetrac differentials in any performance cars. I've only installed them in the front of 4X4 trucks and Jeeps. I have had people tell me that they have some problems doing burnouts with the Truetrac and Torsen units. Seems that one wheel will spin without the other sometimes. Hitting the brakes usually takes care of the problem.
