Originally Posted by Jerry
Originally Posted by TrueWildMan
When you say overdrive, do you mean 4th gear, or the torque converter? When you apply throttle with the TCC locked up, it will come out and feel like a downshift when you apply any significant amount of throttle.
If you're at 75-77 mph, and the transmission drops from 4th to 3rd, the rpm'* will jump up to over 3,000 rpm. If that'* not happening, and the rpm'* are only increasing by about 500 rpm, then the torque converter is unlocking upon acceleration, which is normal.
The amount of throttle it takes to bring it out of TCC lockup will vary from cold to warm temperatures.
Yes, the RPMs go over 3K. I'm certain it'* not just coming out of locking torq. I drive hills and often tap the pedal to get it out of lock after it slows 1 or 2 mph on a hill. On most of the hills I travel this keeps it from going down to 3rd gear.
In that case, since it'* actually dropping to third, and not going back into fourth until you actually shut it off, then back on, doesn't sound like a temperature issue, since when you shut it off then right back on, little to no cooling has actually taken place.
At this point, I would suspect either the PCM, or the computer actuating the transmission.
Have you pulled any codes yet?