I have been looking for a 3.42 or better rear end for my Trans Am. I found an 86 Firebird V6 5 speed at a junkyard. Im under the impression that they did come standard with the 3.42. Am I correct in this? Thanks for the help.

 

yes

 

It should be, but that's no guarantee that a previous owner didn't change it. Dump the fluid, and look on the ring gear for a stamped ratio. Or count the teeth on the ring and pinion gears and do the math. If you don't make sure it's actually a 3.42, Murphy says that you'll get it home before you find out it's a 2.73.

Also keep in mind, V6 means non posi, 86 means weaker axles, etc. In every way other then gearing it's a step down.

 

I knew that it was not a posi but I was unaware of the other issues. Thanks for letting me know. There are a couple 87-89 auto 6cyl cars. I also believe these are 3.42s as well? If so and verified, would post 86 rear ends be a better route?

 

Ideally, you'd be looking for a 91 or 92 rear for marginally stronger axles. Without turning both tires, it'd be good for monster burnouts but performance might actually go down if the tire is spinning instead of putting the power to the ground. Even if you can get it really cheap, it's probably not worth messing with a V6 axle.

Most V8 cars between 85 and 89 were 9 bolts, which are somewhat stronger than 10 bolts, but they don't have much parts support. The 10 bolt is a lot easier to find parts for. Most 9-bolts are 2.77 gears, but there are 3.27 and 3.45 versions that can be found, but except for 1989 models most have the trouble prone iron caliper disc brakes.

There isn't a really good, clear upgrade in the junkyard. Better gears, better brakes, and better strength are all possible, all three seldom come in the same rear.

 

as far as i know a v6 1986 camaro has the same axles as a v8 1986 camaro.i know that the rearends from 1990 up have thicker axles but the earlier ones aren't that bad.

 

Either way, I dont really think Im quite at the power level to worry much about this. This car will pretty much just be a weekend toy. It will see very little track time, if any. But even playing around on the street, the 3.42s have to be better than the 2.73s. The rear ends are cheap so I'll probably just get one and try it. And while Im doing that, rebuild the one that is in my car with new gears and a posi.

 

im running a 3.42 rear from a v6 car.

 

What ratio did you have initially?

 

i don't remember.3.08 maybe.