The one recurring issue with GD RV's (and maybe other manufacturers that use Lippert axles) is leaking grease seals on the axles. There have been a significant number of current GD owners reporting that grease has leaked past the seals and contaminated the brakes. You should make the dealer as part of the deal, remove each hub and check for this. Lippert and GD have been taking care of owners with this issue, even those out of warranty.