Tow Haul Question

[MJarske]

I dont see that my Tow Haul button is working at all. On my Ferd (gas) if I was cruising along in tow haul and pressed the button my rpm would drop as the transmission upshifted. Conversley if I was cruising alon and activated tow haul the rpm's would increase as the upper gear was locked out. I dont see any response at any rpm or speed. how about you guy's with the 6. 7s.

Am I missing something? or is mine broke?

 

[FredMaryLou]

According to the owner's manual it does not upshift. The 'tow haul' on the 2007. 5 slows the shifting pattern. I am looking forward to try it when I start towing my fifth wheel in May. I have decided this must be one 'smart' transmission. It reads temperature, speed, tow haul position and other information to decide when to shift. Fred

 

[MJarske]

Yea, I read that too. I cant tell any difference. . I will be towing this weekend.

I have a few grade to pull. The maybe i can feel the difference... Maybe the transmission and computer are just a heck of a lot smarter than me!!

 

[AKaiser]

Remember, your diesel has significant low end torque that the gas truck didn't, so it won't need to change gears as often. Tow/Haul on your new truck just adjusts the shift RPMs to better use the torque of the engine. In normal mode, the transmission will upshift at a lower RPM to save fuel. In T/H mode, it will shift at a higher RPM to keep the engine RPMs in the max torque band in the higher gear. By doing that, it also serves to reduce "gear hunting" which seems to happen more with gassers.

 

[Jeb_H]

The T/H will also put the transmission in a much better situation to help slow the truck when coming to a stop, it senses the weight of the truck and or load your dragging and will use the lower gears of the transmission to get her to slowing down better with more control and less use of the brakes.



Using the T/H and the jake brake together and tap the brakes to trigger these two to the slowing down or coming to a stop will really just about take full control of the stopping or slowing of the truck and/or trailer. With just very little finese of using the brakes just a little to keep these triggered.

 

[bigdaddycummins]

Jeb H is right if you have your exhaust brake on and tow haul on it will down shift pretty hard when coming to a stop, first time i tried it i was a little shocked at how hard it downshifted with tow haul off it wont down shift like that. iam starting to get use to the converter locking so early it sure runs at some pretty low rpms. i almost get better milage in city than hwy with the low r's

 

[Grizzly]

I dont see that my Tow Haul button is working at all. On my Ferd (gas) if I was cruising along in tow haul and pressed the button my rpm would drop as the transmission upshifted. Conversley if I was cruising alon and activated tow haul the rpm's would increase as the upper gear was locked out. I dont see any response at any rpm or speed. how about you guy's with the 6. 7s.

Am I missing something? or is mine broke?

Well, first of all you can't compare a ferd gasser to a Cummins diesel. Just doesn't work.

 

[MJarske]

Thanks guys,



this is my first diesel, so I am learning s I go... boy do I love this thing.

I cant wait, I'm hooking up the TT in the morning and gonna pull for the first time. The Truck drives like a dream to work and back but I bought it to tow. after towing with gassers in the past I think I'm going to be beyond impressed!

 

[Grizzly]

That's great, enjoy that new truck. Let us know how the trip went.

 

[MJarske]

well, made the trip towing the trailer. the roads were small two lane highways very narrow and lots of switchbacks and curves.

on long straight grades, the trans seemed a little sluggish at times. I found if I shifted down the auto while climbing it would just keep accelerating and then I could shift up as the RPM's climbed. . there was no stopping the acceleration!

I would have thought the auto would downshift sooner but even with towhaul on the auto needed help.



The EB worked awesome as well. On the long winding downhill grades, the EB held the truck and trailer back almost too well at times. I almost never had to use the trailer brake or truck brakes.



Granted these were small mountains by california standards just little coastal hills really. But I was impressed. will be heading to the sierras in the near future then we will see how it performs there.



my freeway mileage was running around 10. 5 on the overhead dropped to 8. 3 on the hills. hand calced at 8. 4 at the end of the trip. a bit dissapointing.

 

[Sky]

I sure hope once the truck gets broke in its better the 8 mpg

 

[MJarske]

I sure hope once the truck gets broke in its better the 8 mpg

Amen to that!!:{