For the last two days my engine has had a bad clunking noise during shutdown. It sounds like when your doors are not shut properly and you turn off the key. I checked underneath and nothing appears loose or broken. The only thing I saw was ice build up next to my oil pan. We had a dump of about 18" of snow and fridid cold conditions -35*F I am hoping this is the cause. Has anybody experienced broken engine mounts on these trucks? Could it be I hope not.