Hi Brenlyn,
Since no one else has jumped in here, I thought I’d at least tell you I feel your pain and pass on my experiences. Our last rig, a 2020 3120RL, had what sounds like the same problem. However, you note that your slides are stuck out. Have you tried retracting beyond the jack movement? On ours, once the jacks (and it was the front, landing gear only) would fully retract, the slides would retract as normal. The same happened on extend – we’d get the rig off the truck using the landing jacks. Then when extending the slides the front jacks would fully extend, then the slides would extend. You could then relevel and everything was fine. Well, in the broad sense, it was fine. Sometimes we’d experience the front jacks creeping down both when set-up AND while towing.
Lippert support was very responsive, and if you’ve talked to them they probably recommended a by-pass test on each hydraulic ram. It’s relatively easy to do, they will send you instructions. On mine, none of the jacks exhibited bypass. However, I’d admit that I didn’t pull the underbelly to test the slide rams. They might also recommend an electrical/command unit test. For this you just unclip the wires that go to the Hydac valve in question and verify it doesn’t move either when commanded to move or when the slides move.
After countless calls to Lippert and several visits by on-site service providers, I came to the conclusion that it must be the Hydac valve that controls that front landing gear. On my rig this was mounted to the driver side jack. This valve is responsible for controlling the flow of fluid into both of the front jacks. In it’s normal “off” state, fluid is blocked from either entering or exiting the ram, and thus it stays in position. When energized, this valve allows fluid to flow either to retract or extend – depending on which way the pump is running. There’s also a way to manually open or close the valve using the hex screw. It’s possible that this manual valve has opened a bit, and allowing fluid flow regardless of the command given. These manual valves turn backward to a normal valve – so make sure you are turning the right way. And, don’t over tighten – they fail beyond just snug. In the manually opened position, the jacks will respond to any pump activity, even if that activity is from commanding a slide to move. I replaced the front landing gear Hydac valve - the first one leaked. A second valve appeared to work, but the problem was still intermittent.
That’s about it for my knowledge, maybe someone else can fill in pieces I missed or got wrong. I was at the point of starting to replace expensive components (beyond one Hydac valve) when we decided to upgrade to a newer rig. Sorry I can’t tell you how this story ends – but I understand your pain. Keep us posted – if for no other reason than my curiosity!
