I have a 2002 2500HD 6.0 LQ4 4L80E.
It has a ProCharger that runs up to 8psi, really big fuel injectors, Snow Performance water/methanol injection starting at 2psi full 500cc/min at 5psi and a Black Bear tune. I pull a big horse trailer over the Colorado Rockies with my Jeep in the back and an RV in front. Full up and only 10 gallons of water the trailer weighs about 11,000 but has been up to 13,560 pounds once.
On long mountain pulls my trans would get very close to the red line. I did not like that so I could not just do a surgical strike I went full on nuclear. I have a universal 26,000lbs trans cooler down stream from the in radiator cooler that is in the Be Cool radiator. Now my trans stays on 120-150 and the engine on hard pulls in Ohio goes all the way to 180-190* in the summer. Winter I have it blocked almost completely to get heat.
My advice, a universal trans cooler and if you need more go with the Be Cool radiator.
