I recently purchased a 91 Camaro Rs, however the rear axle is from a 1987 T/A Formula which gives my car better gears and disc brakes in the rear. This seems to throw my speedo off by a fair amount an i was wondering on how to go about fixing this problem.

 

Welcome to TGO. When you ask questions, try to provide as much info as possible. Regardless of transmission type in this case, you'll have to change the drive and/or driven gears in the tranny depending on the rear end's gear set.

JamesC

 

To expand on what JamesC said, you can usually get the gears from a GM dealer, they will either stock them, or be able to get them in a day or two. Getting them to find out which one you want, is trickier. If they know their stuff, they might be helpful, the ones i've gone to could only look it up based on year of car (ie, not tire size, gearing, etc).

I would highly recommend you fill up your coffee cup, and give this webpage a read;

http://www.transmissioncenter.net/sp...n_______va.htm

It's got a schwack of information on that website there, so get ready for a long read. Once you've digested it all, you should be able to do the math yourself and find out what gear(s) you need. You can pull out the stock gear and count the teeth on the driven, and drive gears, then go back to the website to see which one(s) you'll need to replace.
Or if that much info at once blows your mind, give that company a call, and tell them your situation. They can ship you the gears you need pretty quickly. I think Don is the guy to talk to there, I've spoken with him and he knows his stuff.

oh yea, fill out your car info in your sidebar like myself and JamesC have. It makes it easier for us to answer your questions.

Congrats on the new car, you're gonna love it.