I'm posting this up after doing a search and finding nothing which directly relates to my problem.

History: In January, I put my truck in the ditch and bent a lot of sheet metal up. So far I've replaced almost the whole front clip, a door, all the glass, and have repainted the cab. Now that I've finally found a good rust free bed, I'm looking to start driving the thing again off and on until I have the money to get the bed painted too. However, while driving to town to get a new tire mounted/balanced, I ran into some problems.

First, the rear ABS light is on; not a big concern after looking through others' threads and seeing how many issues can cause this. While I would like to eventually figure it out, it can wait since it's not affecting driveability.

Second, the main problem; the transmission doesn't lock up. It shifts fine through all of the gears. The OD button works as it should, and it holds gears based on the selector fine. Moving from park, reverse, or drive all operate as it always has. It just won't lock up the TC while going down the road.

To see if it would downshift fine, I put the peddle down and it downshifted fine, but then it did something weird. Once it had downshifted, the TC locked up. After some more experimentation, I found that if I was heavy on the throttle, but still light enough to prevent downshifting, the TC would exhibit the same behavior: it will lock up under load, and open while cruising.

I'm currently 120+ miles from my truck since it's at home and I'm at college (had to stay to work all summer), but I'll be going home this weekend. I won't have much time to work on it this weekend, but I'll try to find time to pull codes. I had pulled the codes, but I lost the paper scrap I had written them down on.

After checking codes, what is something I should look into?

Forgot: The speedometer is working fine. I talked to a Ford service tech quick yesterday and he suggested looking at the VSS. Could this cause tranny problems if the speedometer is fine?

 

Check that your brake lights are working properly and in particular, are not stuck on.

 

The VSS should not be the problem as the speedometer is a very good checker for the VSS.

As Lazy K said above it sounds more like some kind of brake problem. A brake problem will drop out the TC lockup and also turn on the RABS lamp on the dash.

 

Subscribing. My tranny does the exact same thing. Same symptoms of locking under heavy throttle and I have yet to figure it out. Shifts perfect other than that. I have the RABS light on also but am not that concerned about it. I have all the stuff to manually lock up the TC with the flip of a switch but I have yet to install it. I would rather have it work like it was designed to though. I know that all of my brake lights work, except for the one on top of the cab (because there is no bulb in it). I figured that it would be on a different circuit anyways. It does however looked like the PO tampered with the brake light switch but everything works as it should. Hopefully we can get to the root of the problem.

 

Locking under heavy accel. may be significant. I am no expert but as I understand it, the PCM will ignore a signal from the brake circuit to unlock the torque converter if the truck is accelerating.

 

After doing some searching, I have a question. Would the RABS system, malfunctioning, cause the PCM to disengage the TC lockup? I read a few threads where the parking brake switch could cause the RABS light to come on and it's a form of braking, just wondering if they could be related. On a side note (and maybe something else to look at) I believe that the BRAKE light in my instrument cluster is burned out. Could this cause problems with the RABS or the TC lockup?

 

Would the brake light "not be working" if I have no harness so there is no bulb load right now? (yes, I drove it to town using arms signals for turning and slowing). Currently, I just have the box sitting on the frame so that it's not in my dad's shop in his way, but I don't have the harness for the rear tail-lights installed, nor is the third brake light installed yet (since it was taken off to paint the cab). Could it be as simple as installing the the wiring harness and putting a couple bulbs in? If so, it'd be a big relief to know that nothing major is wrong. I can't afford to replace/fix the transmission after everything that I'm doing right now to get the body back up to snuff.

 

I have a 1997 F250 7.3 Powerstroke with an E40D transmission that was rebuilt 10,000 miles ago. Since the rebuild I have had some intermittent issues such it sticking in first gear until I let off the throttle then it shifts to second and all through the gears. This has been intermittent. Recently I drove the truck on a trip which after a few miles started sticking in first which i would get it to shift by letting off the pedal. After another 75 miles it would not shift out of first at all and I had no reverse. I limped it to a place that could haul my truck back to where I had the tranny rebuilt. The next day after my truck took a 75 mile ride on a flatbed the tranny shop could not duplicate my problem telling me it shifted fine through all the forward gears and also had reverse.

Anyone have any ideas on what my trouble could be?