Engaging the Tow/Haul Mode doesn't eliminate OD from being engaged, at least my truck doesn't. Hitting the Manual button does, regardless of Tow Mode. Have you tried that? I mean, when you are traveling at the higher rpms that are bothering you, switch to Man, then back to auto. And then back out of the gas almost all the way to see if the final torque converter lockup can be achieved, because that is what is not happening if I've understood your post correctly; it has the final gear, just not locked in torque converter.TxCwbyUS said:
All else fails, have a tech ride with you and the portable scan and duplicate it for him since no codes are posting. They have done this for me on the "cruise disengagement thump".