Numbers on ring gear

[VAL]

Can somebody explain the meaning of the numbers stamped on my ring gear?

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[BigPip]

They tell you the gear ratio. The 40 is the number of teeth on the ring gear. 13 is the number of teeth on the pinion gear. 40÷13=3.07682308. You have a 3.08 rear end. They're installed as a set so both numbers are stamped on the ring gear.

 

[VAL]

Thank you, that was informative. Here's the deal, a couple of months back, I was gonna get a set of 10 bolts front and rear off a 89 Suburban that had 3.73s for $350. But the deal fell through, the guy was offered more money($400) and sold them, after he had already made the deal with me. I thought that was kinda ****** on his part, but oh well. I wanted those axles for the gear ratio. I pulled the covers off my truck today and there it was, stock 3.08s. My fuel economy is like 8mpg, 10mpg on the freeway.
Considering my truck is lifted 6" with really wide tires & wheels(20x12 wheels & 33/12.50/20 tires, and a 700r4 with no lock-up) I was thinking maybe 4.11 might be a better choice.
Maybe the deal fell through for a reason, I don't know.
Anyone have any thoughts about going with the 4.11s with my current setup?

 

[Driver4r]

As long as you dont have to wild of a cam in it, 1904@65 is pretty good for a cruise rpm. And thats with the 4.11's.

Eventually when i get around to mine and have the money, Im going to put 4.88's in my axles when i put the 35's on, and ill look for either a 700 or 4l80. My Cruise rpm at 65 in OD will be 2132, which is basically what im at right now with a 3.08 rear on 32's with no OD.

TO put it simple, YOU will like the 4.11's, and so will your Trans.