Yes, the dash on our GBM Cruise Master was pretty loose. There were some screws that were loose, and I had to put some others in that apparently weren't in the original design. In the center console area near the radio & Heater/AC Controls there is a support brace that had a frequent tendency to loosen and then disconnect. Using LockTite on the mounting nuts seemed to solve that issue.
Your dash is probably different than ours, so all I can recommend is to push & pull on various parts of the dash and see where additional fasteners might help tighten things up.
Good Luck,
~Rick
2005 Georgie Boy Cruise Master 3625 DS on a Workhorse W-22
Rick, Gail, 1 girl (27-Angel since 2008), 1 girl (22), 2 boys (23 & 20).
2001 Honda Odyssey, Demco Aluminator tow bar & tow plate, SMI Silent Partner brake controller.