I tried turning off the O/D switch and it didn't influence it at all. I believe that it is the driveshaft, or at least some component outside of the transmission, because a loud clang accompanies the lurch sometimes.
Another oddity, it was chilly here today, and O/D would not engage, even on the highway. It engaged perfectly yesterday. Do I have a faulty Solenoid, sir?
I checked the fluid this morning and it was still bright and clear.
I think OD is defeated by the PCM until engine temperature gets up to a certain threshold. Additionally in certain applications there is an external temp sensor for the trans and in others it’s internal - part of the OD/LU solenoid assembly which has a thermistor built in. If it sees a low temp you won’t get OD, too hot and OD is defeated as well.
