My Fleetwood Excursion 39S has grease fittings on the jacks. I give them a pump every six months. If they're going to be down for a while, I'll use WD-40 on them.
Bill
Nodwell RN110 out moose hunting. 4-53 Detroit, Clark 5 spd, 40" wide tracks, 10:00x20 tires, 16,000# capacity, 22,000# weight. You know the mud is getting deep when it's coming in the doors.