Transmission Cooler Worth It?

[Shiny]

Anyone have experience with an aftermarket trans cooler for a 2018 Chevy Silverado 1500/5.3 gas?

Chevy does not offer an "add-on" cooler and the dealer parts dpt recommended a "Mishimoto" brand that's $450 plus labor to install!! I don't see a lot of options online. The dealer said it is not a typical issue nor concern which is why there is no Chevy-branded "upgrade" available.

We had an "overtemp event" while towing our 5.0 last summer up McClure Pass at altitude (~8500 ft). The truck's temp monitor was showing hot enough to be a concern but not a crisis. This happened when we got stuck behind a dump truck for a few miles on a moderate grade. We simply didn't have enough speed for airflow to keep the fluid within "normal" range and the fan didn't get it done either.

I'm on the fence about it, given the cost and this being the only time it happened... but I also don't want the transmission to fail nor do I want to worry about it.

Anyone have the same truck and face a similar decision?