Truck specs

He hangs out on "The Garage" page, put Mr.Haney into the search box, you will see that he was on here yesterday. Send him a PM and he will get back to you,probably not as quick as most folks would like but he's a busy man.

 

Fuel mileage has more to do with the driver than the truck. But, a poorly spec'd truck can make it difficult to get mpg.

3.55 rears with a 13 speed is a good compromise. 65+mph run in 13th. 64-52 mph run in 12th. Use the cruise on flat ground, run on the pedal in hills/rolling hills. Even with the newer "aero" shaped trucks, the faster you run over 55 mph the more fuel you will use. Anytime you can run in direct it's better than running in overdrive or double over. Watching the Pyrometer and boost gauge will show you what gear you need to be in. Flow through mufflers, FleetAir filters, ported exhaust manifold and larger turbo gives more mpg too if you use it right.

Currently, I have a 12.7 Detroit, factory 575 hp and with Pittsburgh Power box set on 7 I have 700 hp. I routinely get over 6.5 mpg running at 80,000 lbs. Just ran from Boise ID to Huntsville AL last week with all the wind and still made 6.61 mpg.

 

Some very good insight here.

Thank you for all of the comments and input.

Hurst

 

I suppose that could have been a design flaw in some of them. I have never experienced it or heard of anyone having that issue. On the surface, it seems strange though. When working a lot of hills, 17th would get used quite frequently. But I have heard of stranger things, so there may be some merit to it. And I have the same problem... information overload sometimes.

 

I could see there being some truth to this. I don't think it would cause failure though. I know in my truck (2000 pete 550 cat 18spd grossing 135,000lbs) when I ran in 17th gear (1500rpm@90km/h) in rolling hills the trans temp would run up to 250 degrees. As soon as I got on the highway in 18th(1450@105) the trans temp would drop to 200 or so. Just this year I put an air type cooler on the trans instead of the water type and the temp is almost the same in 17th or 18th.