Bell 206 Isolation Mounts
mlagersson: 'blackhand' was correct when he said look at the way you operate the machine, abrupt cyclic inputs will quickly degrade the isolation mount - it wasn't designed for military-style flying techniques.
Also, 'Chopperlover' was spot-on when he said "...Oil, grease leaks, harsh detergents and rain/sunlight will break down the rubber of the mount making it more susceptible to failing." keep the transmission deck clean and rectify any oil/grease leak from the input quill and/or forward diveshaft coupling as quickly as possible.
DO NOT attempt to replenish the main transmission oil by pouring directly from the can with the cowling in place.