'89 F150 transmission issue

I've got an '89 F150 with a 5.0 EFI and three speed auto. The problem is that it is now a two speed. I leveled off the fluid but that didn't do the trick. The truck is rarely ever driven at 55 MPH since I only use it for local dump and Home Depot type runs. Last night I had to move a couch for a friend, I got on the highway and realized it wasn't engaging third gear. The previous owner had it re-built 20,000 miles ago. Is there a problem inherent with these trannsmissions or the re-build of them that would cause this? I just want to know a little about what I'm talking about before I bring this $500 truck in for repair and get told it will be a $1000 fix.

Reply to
Jim Tiberio
Loading thread data ...

check vac modulator line

unhooked/leaking - no third

Reply to
TranSurgeon

Thanks for the quick response, I'll do it when I get home. Sooo, uhhh where exactly is the vac modulator line?

Reply to
Jim Tiberio

modulator is thelittle can thing sticking out at right rear of transmission, on the back edge

line goes from there to manifold vac source

Reply to
TranSurgeon

I am assuming you mean it is not upshifting as opposed to going to "nuetral" in which case you have an entirely different problem. If it is a 3 speed, you may have a stuck road speed governor. It is located in the tailshaft housing. IIRC, it can be service (unstuck) by removing the ts housing. It is not a 10 minute job, but, it is not too bad or complicated if you have a few tools and are willing to learn as you go. You might also want to check your kickdown to be sure it is not stuck at full throttle position for some reason.

Lugnut

Reply to
lugnut

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.