I had an 07 (new body style) with the 5.3, 3.08 gear and 4 speed transmission. The first season we towed out 5000 lb (dry) Jayco, I hated it. I suspect we were close to 5800 lbs loaded but with the 4 of us in the TV, the 5.3 seemed tired in the rolling hills of central Missouri. I'd leave the truck out of OD and sometimes would have to leave it in 3rd to keeps the RPMs up or the transmission would constantly shift between 3rd and 4th. I hear the 6 speeds are more capable but I sold the 1500 for a 2500.
