Chevrolet Based Class C *UPDATED AGAIN*

I have a 2014 Thor Freedom Elite 23U with Chevy chassis. It has the new L96 6.0 with VVT,a 6 speed 6L90E, and 3.73 rear axle. I have driven over 3500 miles now in 3 months and I am averaging 10.1 mpg - MPG has improved with more miles. Based on my test drives the Chevy was the choice - It has a taller 4.03 first gear and takes off just fine. Also when cruising down the highway both 5th (.85) and 6th (.67) are overdrive so when it downshifts for inclines there is only a slight increase in revs and not much noise. When I test drove the Fords they have the same problem I had towing a TT with my 2001 Yukon. When they downshift on the highway the REVs and NOISE go way up (4th is 1:1 and 5th is .71. I have been driving about 65-70 mph so I could possibly get more MPG at a slower speed. The additional gears provide more MPG and highway driving is quieter and less fatiguing. The only issues I have had so far are the with Thor portion (knobs loose, fell off,etc).