Reverse OK, TC locked in frwd, just changed Solenoid pack

[triumph406]

Well, now I have a bigger problem!! Originally the O/D light flashed, and the TC briefly locked up, even when trying to stop the truck, the light stopped flashing, and the TC unlocked. It threw up a P0743 code.

So then a few days later the TC completely locked up, I was able to drive it a mile or two (in very heavy traffic) with the tranny still shifting, but with the TC completely locked, I had to knock it into neutral when I came to a halt.

Had it towed home.

I changed out the solenoid pack for a new pack. It works OK in reverse, but when trying to go into forward the TC is locked up. I had assumed that the P0743 code being an electrical failure, that changing the solenoid would fix the problem.

Could this be an electrical problem, that allows it to work in reverse, and not forward? Or is the TC (and probably the tranny) toast? I would assume that the TC being locked in frwd and not reverse is an electrical signal to the solenoid, does that make sense?

Can I send a signal to the TC to manually unlock it?

Thanks in advance for any help!!

This was a thread I started from a few days ago.

http://www.powerstroke.org/forum/99-...ng-tranny.html

[triumph406]

Turns out there was a short in the wiring harness that locked the TC up.

[matter]

really? where excatly, cause i've had the same problem for about a month now.........

[triumph406]

Originally Posted by matter

really? where excatly, cause i've had the same problem for about a month now.........

I'm not entirely sure where the problem was.

The truck has a switch to lock up the TC, the previuos owner disabled the switch, but didn't pull out the wiring. So the short to ground happened somewhere between the switch that was mounted in the pillar gage cluster, and where it was spliced into the harness. We cut the wire where it spiced into the harness and cured the problem.

If your truck has ever had a switch added to manually lock the TC I would look at the switch and it's wiring first.

The wire in the tranny connector that locks the TC is purple with a yellow trace. If you check that terminal, and it's shorted to ground then you have a grounding issue.