My 03--40ft doesnt have the wardrobe slide but the style of slides used by WRV, made by HWH, depend on reverse fluid pressure held in the cylinders to hold the slides in. If yours is creeping and you dont see any obvious hose leaks, then its likely the solenoid is leaking back. Dont recall if solenoids can be "field" cleaned but there are lots of threads on the forum about replacement with new or remanuf solenoids.....see: HWH Solenoid theard......
2003 40' MDTS
Garden Ridge, Texas