knocking

My ‘99 Suburban has 98k miles on it. Recent changes made: K&N Cold Air Intake Kit, Bosch Injectors, Custom Tuned ECM UltraPower GM / Workhorse 7.4L Vortec (454) Custom Tuning and a new radiator. Radiator needed replaced. Reason for the upgrades were to improve performance while towing my camper...

I've been looking at buying a new vehicle. I'm looking mostly at 2010 Chevy Suburban and '10 Cadillac EXT's. My father owns a 2008 GMC Sierra Denali and for the ease of it I have been considering buying his truck. In my research I've read a little bit about that engine having some issues...

So I had the bed loaded down with heavy equipment. After I unloaded I started hearing/feeling the thumping sound coming from underneath in the rear. The truck only has 1800 miles and should NOT be doing this. I looked underneath and everything "looks" ok the spare tire seems secure. Any...