A friend's got a '91 Z28 with a 350. The sticker (I can't believe he still has it, lol) says Performance Package on it I think. It's Posi....is there a way to tell what gearing it has? Can anyone guess?

 

The only way to know for sure would be to take the cover off and count the teeth.

 

yep after this long, our cars could have had the gears changed a few times.

just pull the cover and count

 

oh and with it off change the fluid back there

 

double post sorry

 

Well I'm pretty sure these are the original gear. Can anyone give me a rundown of what gear choices came with Posi in '91?

 

well, there was a pretty wide variety. do you have the original RPO sticker? if so, go to the RPO decoder and decode the GU? codes. like, for instance, mine was GU2 which is the "dreaded" 2.73 gear ratio. so just go decode whatever you have...or if you don't have it, then get to countin' son. actually, if you wanna go through the trouble, there is another way...you get a paint marker, put a mark on the driveshaft, and make a mental mark on the tire, line it with a mark on the car. spin the driveshaft one turn, and count how many times the wheel rotates. 2.73 times, 3.73 times...you get the idea...you most likely have 3.42's if your car is all stock...that seems to be fairly popular in the 92s...should be 3.42's if ya got the G92 package...3.08's should be standard, although 2.73's were still available...

Josh

 

If you guys don't mind me asking here but how about for an 82 trans am, what was the gear ration for an 82 I swapped my 200c for a 700r4 and now my speedometer is about 12 to 15 mph off above the car's actual speed. I was told I need to change my speedo gear but I need to know the rear end ration to see what gear I need.

Thanks everyone

Chris

 

well, now on that, unless you have an option sticker you will have to either count teeth or use the method i listed above...good luck guys...

Josh

 

You could also pull the cover and look on the side of the ring gear and it should be stamped on there. Is there a tag on the rear cover?

 

Thanks Screamin'! I'll try the methods you described!