Water pump issue

Agree with most of the comments. Pumps probably OK and air in the system might make the pump run longer than normal. Akin to std problems you might encounter when de-winterizing the rig ... you might consider running the pump with all the faucet valves open (hot/cold including outside shower). If it's air related then that should fix the problem. As far as vibration -- maybe the overflow got some floor boards wet and the moisture makes more noise or maybe it caused some warping which is accentuating the noise ... time may fix or maybe some insulating pads under the water pump (I use old mouse pads)

BTW - turning off the water pump as well as the outside water supply is a good idea whenever you leave the rig. If a pipe develops a leak when your not their or your dog turns on a faucet you got big problems.