Yep, the system is the same whether it be in an F250 or class A. And yes the cruise control on the old cable throttle system will be lazy. This in turns means the throttle needs to open more to maintain speed. When that happens it also makes the trans downshift. It all works together. My Dodge never did have an issue holding a set speed, even in the mountains. It would just always keep the speed what it was set at. Fords system is slow to respond, so by the time the system decides to maintain speed the truck has already dropped 4mph! It's the only thing I don't like about my Excursion.