SailorDon

I just finished a Labor Day vacation 3,200 mile road trip from Houston to Michigan to Barrie, Ontario and back. I was towing a trailer with my Harley Davidson Street Bob.



After adding up the gallons (plus converted liters for Canada fill ups) and dividing into the total miles, the mileage for the trip was 12.976 mpg. Traveling interstate on cruise control at 65 to 70 mph most of the way, I expected better gas mileage than that.

One thing that bothered me was that the transmission was frequently shifting from 6th to 5th gear and occassionally into 4th gear. Cruising at 65, the tach read 1,700 rpm and would jump to 2,200 rpm on the first downshift, and 3,000 rpm on the second downshift.

I wonder if my gas mileage was reduced by all that computer controlled downshifting. By comparison, I used to pull the same rig with a 2001 Chevy Silverado with 5.3 liter V-8 and 4 speed automatic and would get about 15 mpg. That truck was a 2WD extended cab which would explain the better gas mileage, but I didn't think that a Screw with 4X4 would take such a big hit on the gas mileage. The window sticker says 13 city and 18 highway.

It's starting to pick up a slight vibration at 70 mph that it didn't have when it was new. Pehaps it is time to rotate the tires and see if that will fix it.

On the plus side, this is a very nice vehicle for the long haul.

jetmechG550

Did you tow with the Tow/Haul switch on?

drggenballs

Wow that really does sound a little low. I pulled my almost 6k lb boat over 700 miles last week (almost all expressways) at 65 to 70 mph and calculated my mileage at 12.7 mpg. This trip included quite a few hills along the way and the truck never shifted south of 5th gear. I have an fx4 with the max tow package and that (3.73 rear end) may be the difference in the down shifting but I would expect you to get far better mpg than I got. Did you use the tow haul mode? I know a few times after rest stops I forgot to put it back into tow haul mode and notice it shifting too soon and quickly put it back tow haul. I was pretty happy with my mileage compared to what I was getting with my 03 f150. It was an xlt with a 5.4 and 3.55 rear end. That truck never liked pulling my boat and did a lot of shifting. I never got more than 10 mpg with it pulling the boat.

FEfanatic

I wouldn't complain about the mileage too much. That sounds pretty decent for towing a trailer. Heck, I got 12.9 on my last tank mostly highway and no towing. I towed my 19' bass boat a few weeks ago and got 10.8 so you are doing pretty good in my book.

kozal01

iTrader: (2)

X2, im wondering the same thing. towing in overdrive is a sure way to overheat and fry your trans.

ftrucktough

oh boy here we go

These transmissions are designed to shift often... the extra gears are there to use! If load allows, there is no problem with it running in 5th or 6th (both gears are "overdrive"), thus being there is no way to "lock out" either of those gears.

Just drive, the truck will be fine!

As for the OP mentioning a vibration... did that develop while still towing the trailer? Does it still do it after coming back and taking off the trailer? The trailer could be the source of vibration too...

kozal01

iTrader: (2)

theres a reason the truck comes with a tow/ haul mode. read your owners manual, or dont, its your transmission.

from the 2010 F-150 towing guide:

"DRIVING WITH AN AUTOMATIC
OVERDRIVE TRANSMISSION
With certain automatic overdrive transmissions,
towing – especially in hilly areas – may cause
excessive shifting between overdrive and the next
lower gear.
• To eliminate this condition and achieve steadier
performance, overdrive can be locked out (see
vehicle Owner Guide)
• If excessive shifting does not occur, use overdrive
to optimize fuel economy
• Overdrive may also be locked out to obtain engine
braking on downgrades
• When available, select Tow/Haul mode to
automatically eliminate unwanted gear search and
help control vehicle speed when going downhill"

look on page 6
http://www.fordvehicles.com/assets/p...vF150sep09.pdf

2manytoyz

We towed a 5000 lb travel trailer this weekend, a little over a 100 miles each way.

I used the tow/haul mode each way. Kept the speed between 65-70. On the way up, I used cruise control. I noticed exactly the same thing you did. It's dead flat in Florida, and winds weren't too bad, but the transmission hunted every few minutes. Shifted maybe a dozen times in 20 minutes. That was enough. Manual throttle the rest of the trip.

On the way back, did not use cruise control at all. RPMs stayed at 2200 RPMs, transmission did not shift again once up to hwy speed.

That tells me Mr. Ford needs to tweak the programming for the cruise control. Make it less sensitive while in tow/haul mode, so it doesn't hunt as much.

Here's a video with the cruise control on, and the transmission shifting yet again:


Here's a video on the return trip, no cruise control. Happy transmission:


Patiently waiting for a TSB on this one...

ftrucktough

Right, and tow/haul mode uses both "overdrive" gears, and it is common operation for the transmission to shift. It holds gears longer but it still downshift and upshift accordingly on hills to be in the most efficient gear. I'd say read your owner's manual but you have 2005... the transmission is entirely different in 09+ models.

ftrucktough

That does not apply to the 6-speed transmission, sir. there is no overdrive lockout. I repeat, THERE IS NO OVERDRIVE LOCKOUT