https://www.f150forum.com/f38/succes...nction-461560/

 

Call it anything you want, but both 5th and 6th gears are OD. I quite often lock out BOTH and run in gears 1-4. Truck runs better and gets better fuel mileage if used under the right conditions. It kinda sucks that some trucks don't have that option, I was not aware of that.

Just because it is an automatic transmission does not mean we just give up control of which gear we operate in. The transmission will change gears, but it is reactive. It will only change AFTER you've started to lose momentum. It can't see the road ahead and predict which gears you'll need and proactively downshift before you start to lose momentum. I've found that in mountain driving it is best to lock out gears before going up a grade.

I'll often be able to climb to the top in 4th gear while still maintaining my speed, or even accelerating. If I just leave it in DRIVE the truck loses momentum, speed slows and it will have to down shift as far as 3rd gear once momentum is lost. And it naturally wants to go back to higher gears once at the top even though it will just have to downshift again just a short distance down the road. I've driven well over 400 miles at a stretch and never got above 4th in mountains. Got 22 mpg on that tank.

When towing I default by starting out with 5th and 6th locked out. I'll unlock 5th if road and traffic conditions are favorable, but never 6th. I also keep 5th and 6th locked out for driving around town. Speed limits are 40-45 in most places with traffic lights very few blocks. If I get to a place where I can get up over 50 mph, then I unlock all of them. Once again, the truck runs better and gets better fuel mileage.

 

22 mpg...through "the mountains"...bull****. Either you don't know what a mountain is ,or....I don't know...just bull****. Ive driven through the cascades, rockies and the blue ridge mountains more than once, and the only way any full size truck is getting 22mpg is to start at the top and track your mileage on the way down.

 

XLs with the tow package have Select Shift, otherwise nope. My '11 is an example.

Brad