I have a 2009 Beaver Contessa C9 and just traveled from North Fort Myers FL to my home in Michigan on route I found a similar problem in that I had trouble on the steep mountain grades, I made the decision to try to make it home on the steep grades I got down to 35 miles per hour on two grades on the way home. It ran great other than the steep grades , I have an appointment at the Cat dealer in the next few days, I will keep you posted.