I'll second that. We have the 4.7 and QTII. We had no trouble on the outer banks this year, we just aired down to 20 psi and turned off the esp. Even did well in south avon, which is some of the softest sand. I found that using the autostick helped a little also. It seemed to want to shift up early, and keeping the revs higher gave us more control.
If you park on the beach, when you get where you want, pull forward another 10-15 feet, then back up. It helps you to get moving before you start plowing new sand. Don't know if it's a proven technique, but someone showed me about 20 years ago when I had my CJ7 and I've been doing it since.