RPM and MPH

[Rico001]

we just did a 4 day round trip from Panama City FL to New Orleans LA the miles were about 330 both ways not including what we drove around town.

Without using calculators and math, I notice that on the way to New Orleans I used the cruise control on the way over when the truck approached a small incline the cruise control made the transmission down shift and what also seemed like a 3/4 throttle opening and it held these settings fro about 30 seconds or longer after cresting the hill. The engine had a load droning noise like it is under a heavy load while this is happening and it sounded the same when on level ground plus the trans temp stayed at 3/4 hot.
I noticed with cruise control the RPMs were at 3500 and the speed was 75mph. We only made it to Ocean Springs Mississippi. We filled up and went on to New Orleans, we left after 4 days of city driving and filled up and went back home but this time I did not use cruise control. even after driving in bumper to bumper rush hour traffic on the way home we were able to make it all the way home and with over 1/4 tank of gas. With me doing the "driving" the engine ran at 2500 RPM but we were going 82 MPH and I did not need 3/4 to full throttle shifts to go over a hill and the trans temp only went up 1/4 way up the gauge.

Just my thoughts here and nothing scientific here and wonder if others had noticed anything like this with there HUMMER too.~Richard