^^^ what these guys said. Our Kwikee was bogging a few years(hold that thought) ago and Gene's word "groaning" is perfect description. Slid under and sprayed with WD-40. It worked and got quiet. The link between the motor's gearbox and the rest of the step seemed to be the one that made the difference. These things seem to to have a circuit that measures physical resistance and stops trying at that point. For example, if we park next to a curb, shut the engine off and open the house door... Step will extend till the curb stops it. It does not sit there straining till we start the engine again and the step gets a command to retract.
That "few years" thought... WD-40... I made a "note to self" to go back with a "permanent" lubricant and that note fell off my brain. I's been literally years, probably six or so, and the step is still fast, smooth, quiet. WD-40 is a better product than a lot of folk say it is(n't). If I had to be stranded with one spray can it'd be WD-40.