I have a 1989 Ford F150 4x4 with straight 6. The truck has a 4spd tranny and is a gas hog. I never go over 55 on the highway. Set the cruise and let it go. I'm wanting to know if the 5sp tranny out of a 3/4 ton with a straight 6 will be a direct bolt up? Don't get me wrong, I like the 4spd, just not very fuel efficient! I live in a rural area, both hunting and fishing places are at least 30-35 miles away, some farther than that!

My brother in law has an 89 3/4 ton 4x4 with the 6 and his truck gets better mileage than mine. My tach at 55mph is at 2500-2600RPM. His is at 1800-1900RPM. His has a low first, but not as low as mine. Which is fine as I don't pull anything heavy enough to need that low of first.

IS the 5sp tranny in the F150's the same as F250's?

Thanks in advance

Navistar

 

He might have different gears than you, or different size tires. How many mpg are you getting? My '87 300-4spd got mid-upper teens, which is as good as I'd expect. And as far as I know, you'll need a donor driveshaft, as the 5 speed trannies are 4+OD, and are longer than the 4spd. I don't know about the ZF 5spd, but the Mazda M5OD has an integral bell housing and the 4spd with granny gear(tranny code A on the door sticker) has a separate bell housing. Only reason I know that is that I had to have mine welded back into one piece once. Think it's the same bolt pattern, though...