Fournierrandy

I cruise around Alberta also and I find I get the best mileage and also most stable power without shifting around if I lock out 9 and 10th. Last trip I was 25.6L/100km and I am over 8k loaded

Gene K

4x4 3.55
5,000 lb Travel Trailer Interstate Cruise 65 mph (105 kmh)
Usually 8th Gear (First Overdrive)
10 mpg +/- 20%

62 mph in 7th with 3.31 is only about 2000 rpm.
I doubt it will hold 8th in cruise unless you have 3.55. Of course every trailer is different.
​​​​​​

mass-hole

10th is ridiculously tall. I have 3.73 gears in my truck and a 5Star tune and don't even get into 6th that often. My truck's 6th is shorter than your 9th. So between my axle and slight shorter 6th gear I have a pretty good gearing advantage. Unless you are in perfect conditions I wouldn't expect to use 10th at that speed.

YEGdude

25l/100km? Eff
About to do my first tow experience...guess 10/l/100km is a unicorn lol

16IngotFX4

Remind us what the transmission gear ratio of 8, 9 and 10 are please.

Fournierrandy

Guess I won't tell you about the one time In a nasty wind that I was 38L/100km......

Gene K

Source: Ford Technical Specifications
7th - 1.00:1
8th - 0.85:1
9th - 0.69:1 (Actual may be 0.685)
10th - 0.64:1 (Actual may be 0.635)

Several other references list 9&10 as 0 68 & 0.63.