[QUOTE=frcamp;709096]Check the drain and trap underneath the shower, and the putty seal at the drain. Fittings could be loose, shower floor flexing allows movement, you may need to add wooden blocks to stiffen the floor.
there should be a vent or access to see under there
X2 We had the same problem with our 220RBS. Leaking at the putty seal. Dealer fixed it under warranty. Safe travels.
2013 GMC Sierra 2500HD 6.0 Vortec
2014 Surveyor Sport SP220RBS