My truck would start bucking just when overdrive kicked in. I thought for sure the tranny was history, but it turns out that it was actually a defective ignition coil that was misfiring. Replaced the coil (had to test all 8 coils to find the culprit as no MIL light was on), and all was fine.

In my eyes the truck was still new at only 69k miles and for the transmission to jump like that is just really poor quality!!!!

Problem occurs while the truck is in OD between 40-60 Mph. Almost seems like engine miss or cutout. But no engine codes reported. Switch it out of OD and alls well. I've had the transmission flushed twice. Seems to help but always comes back. Seems to occur right after rain. Then during a dry or low humidity period absolutely NO problem.

Transmission feels like it wants to shift out of O/D at 55 MPH but bucks about 5 or 6 times before it finally shifts. I drove the truck out of O/D for about 10 miles with no problems. The problem only shows itself when the transmission shifts into O/D. At 65 MPH or higher it does not have a problem. It is only at highway speeds in O/D.