If you guys want to space out the gearing in your six speeds just mount 315 tires on the truck. I have 3.73 gears with the six speed and after the 315 tires I wish I had the 4.10 gears. I only turn 1900 at 70 and really do need to be going 60 to even use overdrive.

Also, another thing to point out is the diesel engine likes 2200rpm. That is where the milage is at. Most people think that lower rpms = better mpg, and while that is gernerally true on a gas engine, the diesel gets better milage in the higher rpms.

Because of my tall gearing I find that I get better milage in 5th than 6th unless I'm on the highway.

 

Not sure I buy that for all situations; my 4.10 geared truck returns higher fuel mileage at 2000. At least it appears that way because at 2200, the overhead numbers fall into the 17's, where at 2000 they're in the 19's.

But my truck is happier pulling the boat at 2200 than at 2000.

 

Perhaps the sweet spot is 2000rpm, but I can tell you it sure isn't 1500 rpm on my truck.

schu