SOS I have a couple of questions for you about your perceptions on the Transmission because I too drive by feel and am very in tune with my vehicle, but being that this truck is so new I have filed most concerns as being overly observant.
1.) When your transmission felt like it was stuck in 5th was it a feeling of drag or did you notice the rpms being higher? (I noticed this morning on the interstate that I felt like the truck was stuck in 5th, but the rpms were in the 1700 - 1800 range at 70 mph)
2.) Do you notice your transmission more when your going downhill or coming to a stop sign? (I've noticed that rather than a smooth coasting sensation of old you can actually feel this transmission slowing the vehicle down. Either that or the 7000lb chunk of metal is not "gliding" very well.
My other car is a Ford Expedition so I'm used to driving big heavy vehicles most of the time.