Hey guys, I attended a nice swap meet in Stafford Springs CT today and picked up an awesome set of 3.73 gears for a gm 7.5/7.625 10 bolt for 20 bones.

It does not matter to me whether the gears are 2 or 3 series however if they are 3 I will need to purchase a ring gear spacer.

So how do I tell. I know the 2 series gears in numerically higher ratios are thicker but how thick and how do I measure?

The pinion gear has 3 has hash like marks positioned in a circle around the end of the gear where the gear code is (-11-41-GM). Don't want to jump the gun and assume this means 3 series...

The end of the pinion also has a A stamped into it.

Any ideas?

 

They are 3 series.
Unless they are rare aftermarket thick gears - and i'd bet money they aren't.

I'm sure you could measure it to be sure, but I don't have my 3.73 gears out on the bench any more to measure for you. If you know anyone with 3.73 gears for a 7.5" 10 bolt, ask them to measure the thickness. Heck, maybe call up Randys R&P and see if they can give you the thickness of a 2 vs 3 series.