[iverger]

98 Ranger, 4.0L 5R55E tranny 4x4. Its not an F150, but I am desperate for help:

1) I replaced my 98 4.0 with one from a 99 Explorer.
2) The O/D light started blinking and the converter won't lock up.
3) Had the tranny rebuilt at a local shop, problem still exists.
4) Tourque converter blew up and contaminated tranny.
5) Replaced the complete tranny from converter to tail shaft, including TCC and valve body.
6) Spent 3hrs at the Ford dealer last night to no avail.

We are all stumped, tranny shop, Ford dealer and myself.

I think it has to be something on the engine. Since the tranny is electronic what sensors does the ECU take into account when deciding when to send a signal to the TCC solenoid to lock/unlock the converter?

It locks it for a mile or 2 and then seems to get confused, quits and starts flashing the O/D light. It stays flashing until the engine is stopped and restarted.