[Isaac Zachary]

Originally Posted by ps2fixer

I found suggested shift points for the diesel in the owner's manual (diesel supplement), wow I was really over reving it according to their figures. I was shifting into 5th at around 50mph, all the other shifts were based on rpm @2k. I'll have to see what kind of rpm the shifts are at. Same book also suggests idling for 5-7 mins after a long trip to cool the engine, but only 15 seconds after starting a cold engine before taking off. It basically says to wait for oil pressure to rise to normal range. The book doesn't say what year it's for, but clearly it's for a 99+ truck. Looked at the axle ratios in the book, it doesn't even list a 3.55 as an option. I guess I got the highest gearing possible for a factory f250 with the diesel.




EDIT:

Took the truck for a quick drive (still warm from doing some work on it and keeping the batteries topped off). Every gear shift suggested in the manual for best mpg is around 1500rpm, 2nd into 3rd is around 1900rpm (bigger jump in gearing). I'll have to target the 1500rpm shift and ~2000 rpm shift for 2nd into 3rd to see if I get good results. The truck seems fairly happy with those shift points, I think when I was testing before the shift I watched the most was 2nd into 3rd which is the big jump and 1500 is too low for that shift.

Sounds about right to me!