Sled develoved an underhood rattle last week . Upon removing the skid pan to clean the btotom end of road dirt and salt I found the source of the vibration. The front engine mount was loose. There is an aluminum block with 2 allen bolts that secure the mount to the tubular frame which the sway bar passes through. Off to the dealer we go as it is a warranty issue. Mechanic said the allen bolts were longer than the threads in the block. He called Cat and informed them of the problem. 1WASHER,1LOCKWASHER, RED LOCTITE . Good to go. I'm wondering if some of the guys feeling vibration in the runningboards could have the same issue,vibe was pretty harsh.