I've had my '05 lly for a little over a month now and it's developed a very hard shake at shutdown with a small squeal at the end of the rumble. I realize its a diesel, but this is violent. Truck has 139k on the ticker, I'm guessing they are motor mounts gone bad. Been lookin at a set of MA h/p mounts just don't wanna spend the $400 and have it not be the resolution. Whatta you guys think?