Tow/Haul Mode??

[waltnono]

Not sure how this should work. Pulling a 29ft Jayco around the Jackson,Ms around I-20 and I-55. I've notice that if I have my 8.1 gas GMC on cruise and if I hit a slight hill the passing gear will kick in. The pass gear will kick in if I don't have it in cruise but the hill would need to be a little stepper. If I'm cruising on the highway should I have the Tow/Haul mode on, or is that something that you use during take off. Oh I'm getting about 7 MPG running at about 65MPH, man I wish I have the diesel

 

[N Smock]

You should use the tow mode all the time, provided that your trailer is heavy enough. It extends the shift points to higher rpm. This higher  rpm shift takes strain off the tranny. The reduced strain allows the tranny to run cooler. Additionally at least with the Allision box you get auto downshift as early as possible to help with breaking. By the time you reach 65 even the extended shift point will have reached overdrive so there is no point to taking it off while cruising. Hope this helps answer the question.

Dropping back to 60 will help that MPG problem, but that is the edge of overdrive shift point in tow, so just run it up to 60 let off gas allow to shift then resume on the gas.

Nelson

 

[Gary RV_Wizard]

The cruise will often cause an earlier downshift, simply because it is psuhing the go-pedal down trying to maintain an exact speed. With the cruise off, your foot usually doesn't react so fast and lets the speed fall off 1-2 mph before accelerating enough to cause a downshift.

You should use Tow/haul all the time when towing.

 

[FX]

This question has been talked to death on other forums. 
I'm not the expert but have read over and over that when towing to have the tow haul mode on.  Some have said it's OK to have it off, if traveling down a long, flat stretch of highway, but it comes down to what your owners manual says.  I figure the engineers at Ford know more about the engine and tranny than I do.

 

[BernieD]

The cruise will often cause an earlier downshift, simply because it is psuhing the go-pedal down trying to maintain an exact speed. With the cruise off, your foot usually doesn't react so fast and lets the speed fall off 1-2 mph before accelerating enough to cause a downshift.

You should use Tow/haul all the time when towing.

Gary

I'm sure that there are many differences between the Allison trannies on p/u trucks and the version that they put in motorhomes. The MH version usually has a "soft cruise" software factory setting. It can drop as much as 5mph without really flooring it and on a climb won't even try to maintain the cruise speed but settles in somewhere between desired speed and reality  . It is much smoother than the cruise on my SUV.

 

[Gary RV_Wizard]

Nice feature, Bernie.  Wish mine had that. The Allison 1000MH in my motorhome does NOT have "soft cruise", nor does the Allison 1000 variant used in the GM pick-ups.  [Wonder if they ever considered calling that version a "1000PU"?  : ]