found a 2001 2500 4x4 for my son's first truck.has 6.0 vortec,161,000 miles regularly maintained 5000 miles,overdrive trans,that has been rebult with bm shift kit for pulling a tractor but never really pulled due to buying a 3500,ext.cab.runs good good paint and int.looked under and very clean no sign of much oof road and no leaks.do with regular maint. and him not burying the truck should last him awhile what do yall everyday mechanics think?