You may have the system where the front and rear gears are connected by a square tube--the end with the hydraulic ram pushes the gear on that end out/in, and the square tube connects to the opposite end gear and moves it. There are shear bolts on both ends, and one end may have sheared. Or the tube itself is broken, but you should hear some noise from that. This all requires that the belly cover be removed over the ram end of the system to visually see what is moving/not moving.
2016 Tiffin 40 QBH
2015 38RSSA, traded
2005 TK3 #1869, 10 yrs of memories,
2017 F450 KR--one more Ford is it
2009 F450 4x4-died; 2010 F450-retired