Hitches. most everyone has one on thier pickup's suv's 4x4's. They are really a very neglected part of our vehicles even I am guilty of that. The other day i went to hook up to the boat and I knoticed it wasnt sitting properly, so i looked underneath and sure enough loose bolts. Every now and then check them sure would be a bad deal to losse your hitch while going down the road towing your boat trailer etc. only takes a couple of minutes. Either use a impact to tighten them down or use a torque wrench, most of the hitch manufactorers out there will have torque specs for the bolts on thier hitches. Dont forget to check the bolts on your rear bumber if you only use a bumper hitch. I have seen them turn loose.