malott442

I need to put the gear set in the car, and I've been looking at a lot of gears. I know I need a 3 series carrier, but will any GM 7.5/7.625 gear work? Is there something different about a 4th gen rear? I can't get a straight definite answer from anyone....

Also, just out of curiousity, I am stuck b/w 3.73 3.9 4.10. What are the gives and takes? I've heard the 4.10 is weaker than the 3.73

boilertwinkie

iTrader: (1)

If you have a 6 speed any of thouse should work fine. If you have an auto 3.73 is the higest I would go. Gets a little annoying on the highway. Next the gears 7.5 7.65 should work for your stock diff. just check the product number of the manufacturer and call it in. Have you ever done a rear end? Do alot of research and allocate a lot of time if it is your first

TDP

iTrader: (23)

Yes, all 7.5 and 7.625" parts are interchageable.

I'd go 4.10s in a 6-spd and 3.42 with an Auto. The rumor that 4.10s are weaker is simply not true. Of course with more torque multiplication, you will have more of a chance of breaking the gears. That is true any time you use a steeper gear ratio.

01ssreda4

iTrader: (96)

i thought two series gear sets were thicker then 3 series????

TDP

iTrader: (23)

When it comes to the f body, the only 2 ratios that are 2-series are 3.08 (40:13 tooth count) and 2.73 (41:15 tooth count). When you have 13 or 15 teeth on the pinion, the pinion gear has to be a lot wider in order to fit all those teeth. The 2-series ring gears are about the same thickness as 3.42 (41:12) or 3.73 (41:11) gears. The thicknesses of the gears really doesn't amount to much, if anything, as far as strength goes.

malott442

I went ahead with the 3.73's, they should be here tomorrow (prob not, snow) or monday.

A shop down the road said they would do it for 250.

Pretty cheap piece of mind for a shop with a good reputation.


My main concern was the install kit with pinion bearings. summit had a set listed that said up to 98. Come to find out it was just a listing that needed updated. I had thought it would work but wasn't sure.

So, to delay my eventual 12bolt swap, I am using the 3.73's and feel confident they will last, because I don't run DR's, I don't dog on the car anymore, and it doesn't get out much anymore. Took 120k to cause a fail in the rear.....

Not bad!

I twisted the pinion shaft...... never thought that would be the part to fail!