Your landing gear should never creep. You have a leak somewhere whether it's in a line or valve.
I did have a leak in my hydraulics once and didn't know it for awhile as it collected in the underbelly.
I would definitely take it in to get it looked at before I put in cutoff valves. That just sounds like compounding the problem to me
Scott and Liz - Southern NM
2012 Wildcat Sterling 32RL - w/level up (best option ever)
2007 Chevy 2500HD 4dr short bed Duramax w/allison
Reese Fifth Airborne air ride king pin coupler with Sidewinder