Hello I have an 01 f250psd I have a problem,the converter will not unlock in o/d.It apparently does unlock at some point though as it does not buck or die at stoplights.But going up hills at 1500rpm or so the black smoke pours and i run out of power and have to go to 2nd gear.On a side note I pull RVs for a living so the truck gets used fairly regularly for pulling.Any ideas?

 

Have you had any codes read? Do you have a flashing overdrive light ever?

 

The light does not flash,but have not read codes.

 

Mine locks and unlocks about 38mph. Feels like a gear shift. Depending on power demand
I just hit the OD button when it starts to Chug real bad. I don't like pushing the peddle down for it to unlock. It is pretty deep in the peddles range to get the TC to release. And if i'm climbing a hill and the TC is unlocked for very long. The Tranny will cook.

 

Just went and checked,no codes.But definately a problem.

 

What determines when it releases?Is it a vaccum condition or throttle vs. load or what.Just want to figure it out or it will have to go to dealership very soon.

 

Vacuum? On a diesel? I don't think so.

The torque converter lockup is decided by the PCM. It looks at many sensors to decide what to do, the two that are the largest part in this decision are the pedal position sensor and the vehicle speed sensor.