How much can the landing gears lift?

I can certainly tell when my landing gear starts to lift my truck, simply from the sound of the motor starting to strain. When I hear that, I reverse back for a couple seconds before I unhitch. To the OP, I agree that, unless your driveway has a =huge= slope, you've likely got something else wrong that's preventing the fridge from cooling than being out of level. Run your gear down a ways, drop the extensions, chock the wheels, unhook and get yourself level to be sure.

Lyle