Uphill Shifting Question

[Jackpine]

Originally Posted by Habbi98

Jack, What you said makes perfect sense. With that being the case i may look into a Gear Upgrade, to something that is a little more aggressive for towing. As I am not as concerned with my "Non-Towing" mileage because the main purpose of my truck is going to be hauling my camper. I have another vehicle for my daily driving. Any suggestions on Gear size? Would like to be able to run 33's and still have the towing power.

On the "non-towing" mileage i just went on a 600mile trip and was only able to get between 12-13mpg. Mileage was great with the Stock Program and factory manifolds (16-17mpg) but as soon as i replaced the cracked manifolds with the set of LT Headers it went south.

-Habbi-

Yikes! I'm not an expert in any way regarding the effects of LT headers. My understanding is that they CAN provide modest power gains, but that there are so many compromises (to make them fit into the truck) that they may not deliver all that is promised. In addition, if you're still putting the exhaust into the "Y" pipe, you're probably defeating the whole purpose of them.

Cleatius12r (Cody) and 88Racing (and of course, Bill) are much more knowledgeable in this area though. They might have some ideas.

Your mileage sounds VERY low to me though. Was that computed at fillup (miles driven/gallons added) using a correct value for tire size? Putting larger tires on and not correcting for them would reduce the odometer reading at fillup.

With 33-inch tires and towing, I think I'd use 4.10 gears. My truck has 3.75 gears and 32" tires. I think it would be "kinder" on the driveline to use the higher gear ratio if you are towing 5,000 # or so. I suspect your gas mileage would be about the same with either 3.75 or 4.10 gears though. I wouldn't go higher than 4.10. Ford has a funny way of changing the max torque output downwards if the load sensed has dropped too much.

If you have 4WD, you're going to have to change the gearing on BOTH axles. This gets a bit expensive.

- Jack