[Pontiacdaver]

I just bought my 74 Grand Am coupe back, and the previous owner took the original 3.08 Saf-T-Trac and put it in his 75 Grand Am. He put the peg leg out of his 75 in it, but according to my Pontiac Parts Book, 75s weren't available with 3.08s, only 2.56s.
If memory serves, you can't put anything above 3.00 series ring & pinion in a rear that came with under 3.00 without using a spacer? Am I correct on this? If so, is it better to use a 3.08 geared rear and upgrade it t a Saf-T-Trac as opposed to using the spacer to upgrade my existing one?

Thanks, Dave

[Grand73Am]

Actually, the 2.73's and up use the 3 series carrier.

2.56 and 2.41 uses a 2 series carrier. So, no you can't use 2.73's or higher number gear ratios in the 2 series carrier without a spacer. But, a lot of people don't trust spacers. Using a 3 series carrier for 3 series gears is preferred.

But, my 75 Pontiac Service manual shows that 2.73, 2.93, and 3.08 gears were also available in the 75 a-body, so they didn't only have a 2.56. So, if you're not sure what it has, you might have a 3 series carrier if you look closer at it.

[rexs73gto]

It will much eaiser to find & install a 3.00 carrier in your Grand Am then it would be to just ad the spacer along with the rear end. You can use the center section from any A or F body cars that have the posi-trac rear. I always say put in new bearings when you switch the center section from one unit to the next. One thing you need to get a center section from any 73-81 F-body & from the A-body use the center section from any 73 -77. They will go right in with no problem. And because there are so many F-bodies out there you can find them very easy.

[Pontiacdaver]

Thanks guys, looks like I need to do more research. I didn't think there could only be 1 axle ratio, but 2.56 was probably standard. I will get under it this weekend and see what I can find.