I don't know how. Stamped on the side of the ring gear in the 14 bolt rear axle. 1 GM 3977333 9 41 3 77 . Can anyone decode that for me please ? Thank you.

 

9 is the pinion gear teeth, 41 is the ring gear teeth. Axle ratio is 4.56. Should be verified by pulling the cover & looking on the ring gear or counting the teeth though just to be sure no one swapped gears.

 

He said that it was stamped on the ring gear... I think it is impossible to count the teeth on a pinion of a 14bolt, I tried once and you just can't see it without removing the carrier.

9:41 is 4.56, pretty common in the 14bff.

 

Whoops! My mistake. Reading on my phone doesn't always allow me to see every part of the post at once.

Yeah, that is the gear ratio & PN for the ring gear. PN is 3977333.