New here, glad I found it. Have a 07-Sierra Denali that is either a race car or a dog, no inbetween. Upshifts way to early, then requires a lot of pedal to get it to downshift. The interesting part is that my wifes new Yukon XL Denali with same drivetrain does not have this problem. Her's upshifts early as well, but comes out of it quickly, easily, and seamlessly, getting the truck moving again. Seems like the solution is simple, with just a shift pattern change. Any products to help? I don't think I need any engine mods, as it has plenty of power.