I've been hauling the same payload and pulling the same two horses in the same trailer since 2003. All four F-150 4x4 have been equipped with the 5.4 with 3.73 rear end and Tow Package. The '02 had a Super Chip program and 3" exhaust; the rest were stock. I am using a Reese Staight Line WD hitch and the total truck and trailer fully loaded weigh less than 13,000 lbs. Most of my towing has been in the states surrounding Iowa, but I hauled the horses out to Reno, Nevada (I-80) in 2003.

When I turned the OD OFF on the older trucks, I could set the cruise control and I only had to use the gas pedal to help the truck up the steeper hills. In the 2010, I activate the Tow/Haul and the truck is constantly hunting gears and if I try to use the gas pedal to help it up a hill, it looses speed and won't downshift when it should. Last year my towing fuel mileage was between 8-9 mpg, but this year with over 20,000 miles on the truck, I am averaging about 10 mpg. All three of the older trucks averaged 9 mpg when towing.

Am I doing something wrong, or is this performance typical of the new 6-speed transmission?

 

In the old trucks, overdrive was locked out. In the new, it does not lock out OD, but will stay in gears longer or downshift sooner with tow haul.

PS. While towing, you should not be using cruise control. Even states so in the owners manual.

 

ya what king fish said you should not use the cruise when towing. dealer told me that, which blows on long hauls. something about the 6 speeds they have two overdrives (5 & 6) so it will hunt for the right gear. so my dealer said its normal and it would not wear out any thing, but thats how they get better mileage from these trucks? = long flat road and a slight head wind every time the wind dies it up shifts to 6th, then wind picks up 1 MPH and here goes the down shift. i don't like it at all and my mileage was better in my 07 (same set up 5.4 3.55 4x4 crew cab)with it getting 16 MPG my new truck gets 14 with a tail wind

 

The issues is not being able to lock out the higher gears. It's a common complaint of the 09-10 models. Ford brought out Select Shift for 2011 which allows the driver to manually shift, or limit the top gear to say 4th or 5th of the 6-spd.

 

Every time a new model of truck comes out I like it less than the one before it. Pretty soon trucks will have 3 foot beds, extended-mega-crewcabs, and a V8 above 5.0L will be hard to come by. 1/2 ton trucks get less practical and more expensive and crammed with unnecessary luxury stuff every year. Alright, I'm done with my rant now

 

REAL trucks have single cabs, 6 cylinder engines, and manual transmissions!

 

Every OEM still has regular cab 8' bed work/base trucks. And they are so much more capable now than ever before. They are just a lot less common than extended and crew cab trucks. I love my crew cab Lariat pickup with 5.5' bed. I have carried 2000 pound pallets of landscape rocks, 2500 pounds of pool sand for kids sandbox, yards of dirt and mulch, appliances, 16' lumber, 4x8 sheets of building material, ATVs, furniture, firewood. I've towed a car 800 miles with it as well as my 6500 pounds travel trailer. And I can do all that with my family of 5 in the cab, with auto climate control, DVD players in the headrests, and heated seats. That is why so many extended and crew cab trucks are sold. Many people think the beds are useless until they actually have one. While they are a compromise and many things do not fit with the tailgate up, I can do almost the same amount of work as a regular cab 8' bed truck.

 

So this performance IS typical of the new 6-speed transmission. Is there any way of retrofitting the Select Shift to a 2010 ?

I never would have bought the new truck if I didn't think that it would tow as well as the old ones. I can't imagine driving 4-5 hours without cruise control...

 

Sounds like it is time for some custom tuning!

Get you a nice towing tune and put a smile back on yer' face.

 

My manual is a little vague on using the cruise control while towing -
First it says do not use speed control, then it says that if the truck loses too much speed it will automatically turn off speed control on long steep grades, and then it goes on to say that cruise control will turn off if trailer sway control is activated.

Of course, this same manual makes reference to using the clutch to disengage the cruise control - so who knows how much outdated garbage is in it anyway.

Another thing the 2011 models may do differently - the truck will lose a significant amount of speed before it downshifts (If towing with the cruise on), then it will STAY downshifted until the engine load goes away, even if the speed catches back up to where it was going up the hill.