Ok, I cant find any ID tags on my axle anywhere, but I have a 1991 GTA, 5.0, 700R4, with a 10 bolt posi rear. What size Ring gear did these come with and / or what part number do I need for a set of gears, preferably 3.42's or 3.73's. I don't wanna take apart the rearend just to find out, then have to put it all back together only to take it apart again when I do the gears.

 

10-bolt for 91 has 7 5/8 dia ring gear and may have 2:73 2-series carrier. So if you want a gear chage the cover needs to come off to check what series carrier you do have.

 

The RPO code will tell you if the gear hasnt been changed. or if the rpo sticker hasnt been changed. post your G codes.