Roof Top A/C Units bounce/get jarred/vibrate from traveling down the road
There are 4 'hold down' bolts that keep the unit up on roof
They loosen over time and need to be tightened
Remove ceiling grill cover and SNUG up on the 4 bolts
SNUG (40 INCH Pounds)
IF you over-tighten THEN you will need to replace roof gasket otherwise they last for very long time. (Mine is 12 yrs old and still doesn't leak)
IF you over-tighten THEN you will block off the Evap Coil drip pan drain holes and condensation will leak inside RV
IF you over-tighten you can warp RV roof causing puddles to accumulate
SNUG ...