I'm not sure I see a problem
You really think heat is a problem compared to, say?
A Great Big 440 Motorhome pulling a trailer on a hot day? Up, down curvy, back, mountain roads, or negotiating some town, etc. I don't think the converter "knows" what gear it's in, only that it's got a lot of torque on the input and "for some reason" LOL can't turn the output.
N' yeh. I know. Every once in awhile they kill a converter.