My Beaver 2005 CAT C9 400 HP engine over heats when climbing a hill. The Transmission Temp gauge gets up to 230 and the Water Temp gauge reaches 240. Once I start back down the hill both of the temperatures gradually return to normal. If the hill is long enough the Check Engine light and the Engine Warning light comes on. I have driven trucks for years and I have never heard of this. I have spent $1500 on expert mechanics and the problem has not been solved. Any ideas you can give me would be greatly appreciated.