Rear gear ratios for medium/heavy duty trucks

[ChrisB]

It seems as though they commonly run from around the mid 3.xx into the 5.xx, though I think I can remember reading of a 2.90 in an OTR tractor. Maybe they meant 3.90?

I am looking into the plausability of finding axles, preferably with hydraulic only brakes (long shot?), that have good ratio availabilioty in the 2.50-3.25 range.

I believe a Dana 135 can be had with as high as a 3.08. How about the heavy duty stuff or any other medium duty stuff whether immediately feasible to fit under a one ton pick up or not?

[bilbo]

I tow with a direct drive Eaton 10 speed, with 2.90 rears....
driven by a Cummins N-14 at 375 hp from factory.