04 2500 HD 6.0 Gas: While towing my 26' fleetwood gearbox toyhauler (gets very tall in stern and is about 8000lbs I think), my GMC pulls it great in tow mode in overdrive at about 60mph on flat ground while getting 7.4mpg. Get a headwing or slight hill or want to pull faster and it downshifts and drops to 5mpg. I really want to pull this rig at 70mph without it downshifting all the time. Completely stock truck except slightly taller and wider (about 3" taller) tires (those stock tires look rediculous). Have the 411 gears.
What can I do to get more torque power at 2000-2500 rpm?
Or am I screwed and need a diesel or smaller camper?
Pulls great in 3rd but 5mpg ain't gonna cut it.
Thanks.

 

I say go diesel, but thats just me... '

I'm sure someone knows something about tuning ideas, so they'll tune in (get it, tune in?? )

 

he said it, tune. I would suggest the diablo because I wish I had one. My hypertech does great but I like the features diablo has so you can adjust fuel and spark yourself. I think you can even disable the second o2 sensor after the cats too. Its crazy but have you thought about going with even a 4:56 gear?

 

Tune it. And not with a crappy programmer like mentioned above. if you want to see real results you need a custom tune.

Ive got a blackbear tune by Justin. Westers and wheatley also specialize in this.

Ive got about $250 or so in my tune and I really like what it did to my truck. honestly it didnt help my mpg's much if any but the added power and high shift points are great.

got 75% torque management removed, 6K rpm WOT shifts... on 87-89 octane.

if gas goes back below 1.50 I want to try the 93 oct hot tune they say it is nice.

 

Could my torque be limited all the way down at 2300 rpm? I know the tunes work for the full throttle stuff, but I need low end torque. I emailed blackbear to see if they can help, but 5 days later and still no response. I hope to hear someone say tuning helped low end pulling. And the torque is restricted at lower rpm's also and the programs took care of it.
thanks.

 

Get a aftermarket overdrive servo piston. It runs about 60 bucks. All you gotta do is jack up one side of the truck to get underneath and work on the passenger side of the transmission. Very easy to change out. It is a piston plate that will hold onto overdrive longer with more pressure.
http://www.4l60-e.com/

 

When you increased your tires by 3 inches, you lost your tall gears in the diffs. Probably like 3:73 gears now. I'd agree with 4:56 gears. 4:11 gears with 33's have gotta be stressing your diffs and tranny pulling a heavy load now.

 

I'll put the little baby tires back on it before changing 2 sets of diff gears. I know it would help but dang it looks stupid. Justing with Blackbear is working with me now and I think we can find some more torque. We'll see.

 

Cool!! LEt us know how it turns out!!

 

If it comes down to it and nothing else is working, gears aren't that expensive.