Rear Differential Locker

Your class C will very likely have far more traction that your pickup because it has massively more weight on the drive wheels. I can back my motor home up my gravel driveway but my pickup won't go more than two feet up it backwards. In other words, your class C may have more traction without a locker than your pickup does with one. Good diff shops are few and far between and finding one to work on a motor home is even harder. I had to have diff work done on mine and the first two shops did less than desirable work. The third one was a hundred miles away and on the other side of an international boarder but their work was exemplary. You'll have more options if you can pull the diff yourself and haul it to a shop. Looks like East Coast Gear Supply has a few lockers to choose from.