i recently bought a 2003 dakota 3.9 v6 and 3.55 rear end,it shifts out of overdrive at the least hill and a big hill it goes into second,im thinking it needs a 3.9 rear axle with a suregrip,thats what i have in my old 92 and its great,will i lose much if any in fuel mileage?,on flat ground maybe?,but goin up and down hills it just might at least stay in 3rd gear,its actually a little heavier than my 92 but has the same drivetrain except the computer shifts the 03
what say you??

hi

might be throttle psi adjustment ?

The 3.9's are dogs. I don't see what gearing down will get you. A 3.55 pulling up hill in second vs a 3.9 pulling uphill in 3rd, your rpm will probably be pretty close to the same. I think the 03 is heavier than you let on...