HReaume

I have a 2001 Dodge 3500 2WD with the High Output Diesel, 134,000 miles.

I rodeo which involves hauling a gooseneck trailer loaded from 14,000lbs+, currently my truck has the high output engine with NV5600 6 speed manual, bosch 300hp injectors, AFE air intake, and aftermarket exhaust brake.

Thinking of changing DANA 80 rear end from current 4.10 to 3.73 to cruise down the road better. Comparing RPM to MPH in the gears, I should be able to cruise at 70+ vs 65.

Im expecting less low-end torque throughout the gears but still plenty of pulling power.

Curious of anyone's thoughts on this or if they happen to have done this change. Should I notice a change in MPG?

johnh

mine is what you would have with the exception of the dual wheels. my mileage pulling a 12,000 pound fiver was around 9 at 65 ,70 i removed the duals

HReaume

john you have 3.73 and still get low mileage? interesting

AlpineRAM

Depending on the tire size you run now you could try to get tires with about 10% more diameter.
This would net the same result in final gearing. (9.91% taller for a 4.1 to 3.73 swap)

You will need to correct your speedometer anyways, so you might try a smarty, (or change the tooth wheel in the rear axle to give you the same amount of pulses per mile as the stocker)
(235/85R16 to 255/85R16 would net you about 4% taller gearing)
If you cruise at 70 instead of 65 your fuel mileage will suffer. (simple laws of physics)

HTH

johnh

my '95 powerstroke got 16 pulling the same trailer the same speed

SIXSLUG

Backing your trailer will increase speed and hamper maneuverability...just something else to ponder....