anw7405 wrote:
I tried tow haul. I tried no tow haul. I tried manual. 6 th gear is out of the question. It seemed like it needed one more gear between 4 th and 5th.
It sounds like the trans is shifting a lot between 4th and 5th gear. If that is true, lock out 5th gear. Every time the trans shifts gears as well as unlocks the torque converter, the trans will heat up more that your OEM cooler is designed.
Lock out 5th gear, cruise in 4th at 60-65mph, use tow/haul mode. The 6.2L makes more power than the 6.0L, but the 3.73 just about makes up for it in terms of power to the road. Additional, higher capacity trans cooler may be needed since you are in the south. And transmission shop can do that. The 6.2L will happily spin at 3000rpm all day long and providing better throttle response, better cooling, and likely better fuel economy than constantly shifting. Do not use cruise control.
