I'm picking up a new 2004 2500HD w/6.0 and 4sp Auto.
I could only get a 4.10 posi rear axle.

I'm concerned that the RPMs will be too high to travel for long periods of time at 70MPH+ (not towing anything, just light camping stuff in the back approx. 1000-lbs )

Any "stock" 2500 owners care to report their RPMs ??

Thanks,
~Rob

P.S. If you *did* put on taller tires, did it reduce your revs much?

yoour overdrive will allow you to run fine at 70+ and yes taller tires gives you lower end gears. I went from 245 to 285 and my gearing is approx 3.81...J

Thanks for the quick reply!
Do you remember what the tach read at 70mph?

It wasn't like 2500-3000 was it? -That's too high!

mine runs around 2100 to 2200 at 70

Well, just drove back from Dave Smith GM in Idaho ---> Seattle, WA in a new 2004 LT (4.10 posi)

(Ave 63 mph // 16.1 miles per gallon // 372 mile trip)

Revs are higher than I anticipated:

60mph = 1900
65mph = 2100
70mph = 2300-2400

This is with the 6.0L motor.
2500HD short bed

Anyone know of a easy calculator to see how larger diameter tires will bring this done? -I think my 245/75/16 = 30.8? -May need to bring that up to 33.0+

I have 4.10s with 35" tires (315X75X16) (You will need a lift) my RPMs are about 1900 at 70MPH.

I have stock 3.73 and 265's and mine are about the same as NW's.