This problem has been around for many years, OEM has made some changes, but the main problem is the shrouding around the radiator.
(1) They suggest using a bushing for the ECU Temperature sending unit? It moves the pick up away from the coolant.
(2) Before reinstalling the OEM radiator, fabricate shrouds for left, right and the bottom of the radiator. Use the OEM shroud, but remove the lint screen and seal that opening.
(3) Wrap from the exhaust manifold to the catalytic converter, using Header Tape. Not-OEM
(4) 50/50 coolant mix, water or additives will not work.
Not recommended by the factory, but I use this test to create a benchmark.
Run the lift until you reach operating temperature. Timed test.
Hold the accelerator on the floor board and operate the hydraulics, until you get the code E32. Most trucks will code out within five to seven minutes. Make the above modifications and retest, it should improve by twenty minutes, which will solve you problem.
In severe applications (Cotton) you may need a transmission cooler, it is always a good choice, but not a substitute for the above modifications.