Does anyone know how to tell the difference between the two sizes of ring gears? The rear end I have is a 10 bolt out of a 85 iroc 3.42 with disc brakes and was an open diff. I have ordered a powertrax unit but I dont know what size gear I have for sure. It is also has 26 spline axles.

 

I would just about swear on it that you have the 7.5. If I remember right they switched to 7.625 in 89 or 90 along with the 28 spline axles.

 

they're the same, gm changed the name or how they ID them, nothing else is differant, or they both interchange.

 

Come to find out after giving it a good bath on the inside they stamped the ring gear. 7.625 was in it. But on the 89 rear end I dont see it stamped anywhere. Jegs told me as well that full size cars were the only ones to get the bigger ring gear but I guess there is no way of really knowing unless its stamped or you measure it. Thanks though

 

don't think i'd believe everything jegs told me. they don't even list a 7.62 ring gear from richmond or jegs, all 7.5, because they're all the same.