so i have a question for those of you more knowledgeable to transmissions and towing. my roommate has an 06 f-150 (fx4 with the 5.4ltr for what it's worth) and when i was riding with him yesterday (not towing anything, just regular driving) he turned the overdrive off. i asked him why he did that and said
him: "ive heard from a few people it helps save the transmission and get better gas mileage. i've been doing it about a week and i did get better gas mileage"
me: "how does it give you better gas mileage exactly?"
to which he proceeded to show me - as we were driving at about 45 mph he showed me how at that speed he was a steady 2,000 rpm(ish) and that when he got on the gas just a little it only went up to around 2,200.
then he turned it off and the cruising rpm at that speed dropped to around 1,600 to which he applied the same amount of gas and it shot up to like 2,800 before descending back to 1,600 when it let off. he said..
him: "see how when it just stays up there and doesn't jump real high when you gas it (with OD off), but when it's on and you gas it jumps up real high"
me: "if you say so. i still don't know why cruising at a higher rpm to keep it from "jumping" when you gas it is gonna save you any gas like that since it's using more fuel to cruise than it needs to maintain that speed"
My question is - from experience has anyone ever found this to be true? i can't see why in this day an age one of the biggest car manufactures in the world would make a truck that gets worse gas mileage in a non towing mode and how cruising at higher than required rpm will ever save gas.