George,
What you describe sounds normal. As you climb, engine RPMs will tend to drop, reducing fan and water pump rotation speed. Thus the engine is seeing reduced coolant flow and reduced cooling air flow through the radiator. At the same time, the engine is being put under a heavier load due to climbing the grade. Thus, engine temperature will rise. The only way to combat this is RPM. Downshift soon after you start climbing and keep downshifting to keep engine RPM in the 1800-2000 range. Also, take the transmission out of Economy mode when in the hills. The last thing you need is to have the transmission programmed to keep RPMs to a minimum while climbing.
Steve