Thank you for the reply. I have the supplies to change my transmission fluid This weekend. Just hit 31,000 miles. Doing the rear diff as well. Bought the truck with 17,000 miles and unsure if it’s been done before.In my case, fluttering RPM's was fixed by an ATF fluid flush. I suggest doing an ATFx1 every other oil change on these transmissions (i.e. earlier than the maintenance schedule). The vibration/rumble when re-engaging throttle after a small decline was fixed by disabling the VCM using an aftermarket device. Finally, the dealer replacing the torque converter fixed neither of these issues (and wasted a perfectly good converter).