Most dealerships these days use "additives" to clean out the system during the flush, so that helps with any loose debris issues during flush. They will raise the truck and run it while running the additives as well to clean the system. If you do your full flush this time, you can probably get by with a drain and fill from now on w/ regular maint. My dealer runs the chemicals through on my drain and fill, so i shouldnt have to do the full flush for a while.