Gears

If you like your highway mileage stick with 4.10s.... I miss mine.

But the 4.56s sure make it fun to light up the 35's :)

I have 4.88's on 35's and at 70 mph push 2500 rpm, but I plan on 37's! I'd say 4.56's, but 4.10's will get the job done.

Edit:
I used one of those rear gearing calcs online, to be exact I'm at 2296.48 rpms at 70 mph with the 35's. Kinda hard to tell when your looking at the gauge and it might be off a touch, who knows....

4.56 or don't even bother with it

haha well i definately need something different from my 3.08s i am just afraid of killing my mileage thats all and its pretty split half and half. I think i will go with 4.10s but just out of curiosity what do you guys run for rpm's at highway speeds? Thanks for all the help

I turn 2296.48 running 70 mph, that's with 35's, 4.88's, and the 4L60E tranny. There is a decent calculator at: Transmission / Rear Axle Gearing the only thing is, it only goes up to 4.56 gears, but I think 4.88's would be overkill unless you plan on going bigger.

With the 4L60E, 35's, and 4.10's running 70 mph you'd be at 1930 rpms. With the 4.56's running 70 mph you'd be at 2147 rpms. Not a huge difference, but throw a trailer behind it and you'd want the 4.56's, for the torque!

just do the 4.56, be much better and your tranny will love you more

Thanks for all the help guys and that website was also helpful. 4.56s it is.

Your pinion gear is gonna be tiny, and weak. I hope you're not gonna pound on it too much.

The pinion gear on the 4.56's is a great deal smaller than the pinion gear for he's factory 3.08's, but the 10 bolt by itself is very weak unit. For daily driving and occasional offroad use he'll be fine with the 4.56's. Alot of the lifted guys run 4.88's and 38's and do just fine daily driving and some offroad. Now, get up to the 5.13's in a 10 bolt and you'll snap a pinion under heavy torque quick as hell. You could always upgrade to the 14 SF later down the road....

I have a set of 3/4 ton axles laying around i just don't want to buy new wheels.