What did they change from 2001 to 2008 1500
 

I just bought a 2008 1500 Single Cab, short bed, with the 4.8 V8with upgraded GM polished wheels ( 20IN ). I have 6500 miles on it now and have found some interesting things.My wife had thesame truck( except for the 20in wheels ) and i drove it all the time.The 2001 truck was a little slow at take off but when the RPMs got up it would run great!!My new truck is exactly the same...maybe a little moreresponsive attake off then the old one. The thing that is getting me is i live in TX. Mostly flat areas. When i set the cruise on the new truck at 70 mph and i come to a small rolling hill, it downships into passing gear and puts me in the seat!! It only downshifts for a few sec. and then back to overdrive. On my way to work ( 30 miles small rolling hills ) it downshifts at least 4 times. However, when i set the cruise at 80mph it does great!!! Not once. The other truck never did that. The only thing i can think of is that at 70mph i am at about 1700-1800 rpm which seems very low. Maybe they changed the rear end gear to get the mileage? Not sure, anybody know whats going on? Dont want to be putting a tranny in this thing in 3 years!