So, I just bought a 97 F250HD with 5.8 and E4od. I bought it primarily due to the near-perfect body and interior. The owner was an elderly man who stated that the automatic transmission was going out. My plan was to put the ZF sitting in my garage into it and convert it to 4wd anyway, so I didn't care about the trans issues. Now that I towed it home and am starting to tinker with it, I took it for a drive and here is what it is doing:

It wants to idle at about 1200rpm, the tach seems to be working smoothly.

When driving, it easily goes into first and reverse as it should. Taking off in drive, it goes through first, into second, and then rapidly oscillates between 2nd and 3rd (maybe 4th, I cant tell), very annoyingly. If manually shifted, first and second work just fine.

The speedometer is very glitchy. You'll accelerate and it wont move, then snaps to like 15mph on the guage, then to another number. It does not move smoothly like it should. Also, it may take a second or two to go back to zero when stopping.


I don't know much about the E4od, and have been reading that the speedometer issue may be related to or even causing the transmission issue. When I get around to doing the ZF swap, I assume the speedometer will still be an issue. I'd kind of like to know, and maybe fix, the issue before doing the swap later this year. So, what do you guys suggest as the starting point?

 

Probably VSS sensor in the rear.

check codes first.