go online and find a speed / rpm calculator, there are lots of them out there. Then figure the speed in which you plan to drive most in. Gear the truck so its in its power band at the speed you wish to drive. 235's are most efficient in the 2100 to 2300 rpm band. Gear it to high and the motor has to work to hard, to low and you are wasting rpm.
I would think a 3.08, 3.23, 3.42 would be about right with the 3.42 for real hilly and 3.08 for flatter ground.
I run a 3.08 with a 250 engine, its fairly flat and mostly highways so I can keep up at 70 pretty easy. Around town its a little doggy, but I can live with that. I changed out a 3.42 to the 3.08, highway driving was much easier and less stressful.
Joe
Last edited by Joe H; 09/09/2011 3:18 PM.
