Mileage observations
We just returned from a 4000 mile road trip. Flatlands, hilly, mountains, wind - everything but rain! Over the coarse of 29 fuel stops and trying many different speeds, gears & rpms. I think I foun...
Forum Discussion
hotpepperkid wrote:
Gear ratios for the Ford 6R140
1=3.974
2=2.318
3=1.516
4=1.149
5=0.858
6=0.674
I tow a 11,000 lb 5er at around 68 on the interstates and it runs in 6th gear. I will down shift to 5th to longer hills but doesnt on the short ones. So maybe I if lock out 6th I might get better millage??I wouldnt ever shift. Would running in a lower gear than the computer requires cause it to run hotter?
Must be an automatic since there is no 1:1
Yes, always OD will create more heat in the trans. When the output spins faster than the input on the trans there is a lot of stress on the gear, and why it makes heat, OD towing is not recommended unless you are going downhill or have a decent tailwind. But, this really depends on the ability of your particular trans.
Looks like you have two overdrives, but 5th will heat up less than 6th in your case.
If there is a "tow mode" button, then just activate it and let the truck do the thinking most of the time.
Running a low gear at the same speed… On the engine your EGTs will be lower with faster rpm due to more air running through, or maybe it is that less fuel is needed with each cylinder. My EGTs drop a few 100 degrees when I downshift (mine is a turbo, and I am not familiar with non-turbo temps).
On the trans you might have lower trans temp when closer to the 1:1 gear ratio, this means that the gears are spinning less. On a manual, in the 1:1 gear, the gears are not spinning at all, so the heat will just come from the engine. In your case I suspect that 4th gear will generate the least amount of heat at a normal speed.
You should not have to worry about gearing and engine heat, a good radiator should handle the engine heat, but you do need to watch the trans temps. Get a good trans temp gauge and drive according to trans temps. Heat kills transmissions.
I don't want to go into explanations, better to research this on a transmission dedicated site that is specific to your vehicle. My goal is just to make you aware that there are things to watch for.
