My 2007 Tahoe easily pulls tandem axle trailers well over 5000#, closer to 10k with ease. In fact, it runs in V4 mode on level road at 70 mpg with the tractor behind on a car hauler. There is a digital on-board transmission temp reading you can watch. I believe that's what the limiting factor is. Its not frame strength or brakes. The Tahoe frame is based on the 3/4 ton truck design (whereas the base Suburban is based on the 1/2 ton frame).