Engine/Transmission (1998.5 - 2002) transmission starts out in third when warm

[Jerry J]

I am lost. Transmission works great until it warms up and then won't shift back to first. Starts in third, then overdrive, then lockup. I have the truck at a transmission shop for a new torque converter but just before I brought it this happened. He put in a new PCM, etc. but still this happens. To me it seems to be running warmer then it used to but not overly hot. The transmission guy only rebuilds them so this is a challenge for him also. anyone ever have this happen. Is it possible my pac brake is causing a problem?

 

[cerberusiam]

Year of truck and any mods might help narrow it down. However, the RE was prone to failure of the gov transducer and\or solenoid that causes that symptom. Usually it is the transducer supplying faulty info once it is warm but both should be changed together if they have any age on them.

Secondary to that is the VB harness for these pieces, it likes to fail with age and shorts things out. It is probably a good idea to replace it also.