I have a new coach with a 400 ISL Cummins and Allison 6 speed. In trying to climb I-70 west of Denver I experienced overheating. Cummins said Chasis problem and sure enough there were 2 bulletins regarding overheating. One was a shield and more vents and the other was a larger hydraulic cooler. After two weeks in the shops I still have the same problem. And downshifting to keep rpm's past 2000-2003 only helps on short climbs. Everyone is passing the buck so could there be any other fixes?
Tiffin Allegro Bus 2006 40ft
2006 Saturn Vue