Won't shift into OD.

[Will Presley]

Hey kids, I have a '94 eddie bauer 4x4 explorer and it's had some trouble lately. A couple of days ago, it wouldn't stay in overdrive. It kept going back and forth between 4th and OD. Then it just wouldn't go into OD at all. The transmission was rebuilt a few years ago. Is the overdrive controlled electrically? If so, could it be a fuse or some other electrical aspect that is causing this? Or is my transmission starting to die?

 

[RaiderKC]

It it anything like mine, the OD sliped and then reverse went out, mine is toast, hope this helped, and welcome to the site.

 

[Sams01XplrSprt]

welcome

 

[BrooklynBay]

Welcome to this forum! I've moved your thread into the transmission section. It's possible that the overdrive band needs an adjustment or the servo is leaking, and can't hold the band in overdrive.

 

[Will Presley]

Thanks! I'll have that checked out. I appreciate your input!

WP

 

[MrShorty]

Is the overdrive controlled electrically?

yes

If so, could it be a fuse or some other electrical aspect that is causing this?

Probably not a fuse, as I don't believe there is a separate "3-4 shift solenoid fuse", but it certainly could be some other electrical fault (loose connection or similar) causing the problem.

1st thing I'd do would be to get a wiring diagram. 3-4 shift solenoid circuit (and the torque converter lockup clutch circuit, for that matter) is a pretty basic DC circuit with the computer acting as a ground side switch.

I'd probably pull codes to see if there are any faults reported that might explain why it won't shift into 4th gear.

I'd probably set up a voltmeter to measure the voltage drop across the solenoid. Then I'd use the output state test (see my notes on pulling EEC-IV codes) to see if the circuit responds to the PCM's commands. If that looks ok, then a road test to see if the PCM commands the transmission to upshift. If the computer is commanding the shift, but the transmission isn't responding, then the problem is most likely a mechanical/hydraulic fault inside the transmission as BrooklynBay suggests. If the computer isn't commanding the shift, then I would proceed to figure out why the computer isn't commanding the shift.