Transmission temperature climbs on long grades

Write down what you already tried. A second data point from another 2023 GMC Sierra 1500 owner helps more than a generic diagnosis. Then you'll know the next fork. This is from a 2023 GMC Sierra 1500 in Denver / Front Range. I'd want that in writing, not as a promise. I'd sleep better after that step, even if it finds nothing. Might be overthinking it, but I'd rather overthink than overspend.

Don't overfit one forum story to your car. If it still isn't clear on the 2023 GMC Sierra 1500, a specialist hour can be cheaper than another round of parts. I'd do that before spending real money. Had a similar mess a couple years ago and that's what finally sorted it. I'm in no rush to be a hero on it.

Owner notes beat generic advice here. On the 2023 GMC Sierra 1500 in Denver / Front Range, I'd fix the thing you'll notice every day before chasing spec-sheet extras. That's where I'd start. On “transmission temperature climbs on long grades,” that was the fork that mattered for me. Verbal 'we'll take care of it' is not a plan. Climate here is different, so treat that as a local data point. That's my plan before I call anyone.

I'd keep this practical. Verify the cheap/easy branch on the 2023 GMC Sierra 1500 before a big repair or a big spend. That's where I'd start. This is from a 2023 GMC Sierra 1500 in Denver / Front Range. I'd want a dollar figure or a measured spec, not 'should be fine.' This is me being the wet blanket on purpose.