Lippert owns Happijac and just recently someone on the net had a clutch/gear issue with a slide mechanism.
I'm sure the type of mechanism depends on the age of the unit but the picture posted looked like a 6" version of the Happijac truck camper jacks. Same power head.
If that's what you have, it definitely has a clutch. The clutch is adjustable, but I've never adjusted one. Two of mine were having problems. I sent them back to Happijac, they reworked them, and all has been well since.
If that is the case and you have to send them to Happijac for warranty rework, mine took about 2 weeks.