This happened to me recently> Lippert said the fluid is getting past (something) and it is equalizing. They told me that it could go all the way out, there are no "stops" built in. They recommended a slide out lock, (which we could not find on our way home from TN) or to get a 2x4 and wedge it in between the wall and the lip of the slide out. Basically like people do to secure their sliding glass door in the house. We stopped at Lowes and had a 2x4 cut. Lippert then told me how to override the hydraulic pump because it quit working completely. It was not hard to do once they told me, but I would have never figured it out myself. Lippert Tech support was very helpful, thankfully.
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2016 F 350 FX4 4WD,Lariat, 6.7 Diesel
41' 2018 Sandpiper 369 SAQB
Lovely wife and three children