To start out with my truck is a 2wd 1994 F150 extended cab, straight 6, with the E4OD. Truck only has about 108k miles on it.I've owned the truck for 3 months now and have been trying to fix it's shifting problem.


When I first got the truck I checked codes KOEO (121 and 452 - TPS and VSS respectively) KOER (all clear) and hit the forum. The cruise control worked intermittently, so I thought it would be an easy straight forward fix.

Long story short I've replaced:
TPS, VSS, PSOM (this fixed my cruise control), Neutral safety switch, and Shifter cable.


I've checked all my vacuum lines and the truck had a complete tune up with new plugs, wires, distributor cap and rotor, and coil (all Motorcraft).
The trans fluid is not burnt, discolored, and is at the proper level.


I cannot remember the name of the plug, but it's passenger side on the trans. It's firmly seated and seems to have a good connection.


As for trans shifting:
Harsh shifting and some lurching when shifting to numerically higher gears. Harsh shifts between 3 and 4 up and down.
I've been watching the Tach more closely lately and sometimes when it shifts into second it will initially start at one RPM rating then drop 300-400 rpm and continue through the gear. (Not sure if this is torque converter related?)
The transmission shifts totally fine when cold. I start it up in the morning and drive about 3-4 miles before it stops shifting smooth.
Also the transmission shifts fine between gears 1-3 if I'm carrying a load. I towed a car a few hundred miles and all gears shifted great except kicking down out of OD to 3rd.
Truck seems to shift better with the A/C on as well
I do get a little shimmy driving at a steady 40mph (Torque converter?)


My last code check yesterday was: KOEO all clear, KOER all clear, continuous memory 334 - EGR valve closed voltage high (I have an extra EVR to put in - should take care of this)


I don't believe my 334 code has any bearing on shifting, at least it shouldn't. I've combed through the forums and exhausted pretty much every option I can think of. I think I've narrowed it down to either torque converter or the transmission itself, but I'm not terribly experienced with automatics outside of the C6. I find it strange that I don't have any trans related codes when clearly something isn't working right.

Any advice or thoughts on which way to go from here would be greatly appreciated. Thanks in advance

 

With the problems you have and given the age of the truck, THE 1st thing I would do is pull the PCM and check for Leaking, Bulging capacitors.

I have (4) F-150's. (2) '92's and (2) '95's. (3) of them had leaking capacitors. And when I swapped my '92, 302 to MAF, the A9P Mustang computer ( I have 3 of them) had 2 leaking and corroded Capacitors.

 

Thanks timbersteel, I feel dumb for overlooking that. Just pulled the PCM and it has 3 leaking capacitors with corrosion around the connections. One of the connections is totally disconnected!
New PCM on the way. Hopefully that’s the culprit...

 

New computer in and it kind of half fixed the problem. Shift from 1-2 isn’t as harsh but still a rough. The shift down from OD to 3rd is still harsh. But if I press the OD button to get it to downshift it’s smooth. Rest of the shifting is fine...
Either way the computer did need to be replaced though.