I have a 2011 F 150 with the 3.7 liter engine and the towing package. It currently has 15,000 miles. I towed a trailer from Detroit to Nashville with maximum towing weight for the vehicle, 5800 pounds. I had not used the Tow Haul feature before. When you are braking coming to a stop, the transmission downshifts and holds the gear which is a great feature. Twice when I was going down a steep grade, I applied the brakes and it downshifted, but when I let off the brakes and accelerated it was very hard to get the transmission to release from the gear it had downshifted. I worried that I was going to damage the transmission. Is this normal?