NEED ADVICE
38 Ft 1995 Country Coach Magna, 300HP Cummins 8.3L, Allison MD3060 6-speed, Banks Stinger package.
GVWR is 32,000 lbs.
Mileage running about 65mph is roughly 8.5mpg.
Mileage running about 55mph is roughly 9.2mpg.
No problems up/down hills towing Subaru Legacy Outback - about 3400lbs
As far as maintenance tips, do what the manufacturer says. In addition, I added an external bypass filter and also have oil analyzed at each recommended change interval.
Mike