i have a 1986 trans am it came with drums and 2:73 in a 10 bolt can anyone tell me if its a 7.5 or a 7.625 rear, i believe its a 7.5

Doesn't matter. 7.5 and 7.625 are the same thing.

not true, these is a small difference between the two, the ring gears are the same but the inards are different, i am looking into a powertrax locker and there is one for a 7.5 rear and a 7.625 rear...

Look again. There is absolutely no difference except for a 1/8" difference in the size of the gear.

look again... go to summitracing and enter part # pwt-1930-lr and part # pwt-1932-lr one is for a 7.5 rear and the other is for a 7.625 rear. there must be some kind of a difference

The 1930 is for 26 spline axles, the 1931 is for 28 spline axles. There's also the 1932 for 26 spline axles with 7 5/8" gears. Since the locker has to surround the gears and carrier, I would imagine that the 7 5/8" models are slightly larger inside.

Apart from the size of the gears, there's still no difference in the rears though. the 7.5" and 7.625" gears can be used interchangeably. If you want to know what you've got, open it up.

I dont know what the difference is but the 1930# is listed for 85-86 all engines and the 1932 is listed for 82-84 4cl and v6 They both are for 26 spline I think you need a 1930. contact Richmond to get the correct p/n before you buy the wrong one.

if you go to Auburn Gear - Home there is a spec page which shows the dimensional diffferences between the 2. And it won't work properly if its the wrong one. As i got the wrong ond had to get another carrier for the corrct fit

hey man what up, since im buying it from you later today, i assume that you now have a 7.5 rear with 26 splines, as this is what i have now, what did you have before? is the size difference caused by the carrier, ie series 2 and series 3 carrier?