We have 2008 HR Endeavor and have experienced the same chime. I have found it to be a "false reading" of the automatic leveling system. It seems that occasionally, the control module on the window console will flash all the LEDs, and chime incessantly, either in wet weather, or sometimes when stopping or turning.
I had my dealer check the system, and some adjustments were made to the sensor(s) that determine a jack is partially extended. This seems to be the root cause of the problem with HR and all Monaco products.
I was told to ensure that the shiny exposed part of the jack pistons were clean and should be sprayed with a good grade (I use food grade) silicone spray prior to raising the jacks. This has seemed to minimize or eliminate the problem. Do not use WD-40 or any petroleum based lubricants on the jacks as it may damage the hydraulic seals. Also, check the hydraulic fluid reservior frequently to ensure it is full, as a miniscule amount may leak out with every jack leveling evolution.
