Just one thing to think about is the fluid flow path. Almost everything we worry about with temps (bands, clutches, and seals) are all fed directly from the filter pickup in the pan. Obviously these are the components to be most worried about when temps get high. The last thing to be fed internally is the converter, which creates the most amount of heat. If you measure the trans cooler line out of the trans, you’re measuring a lot of heat created from the converter that will never directly get back to the clutches/bands/seals.

The converter by construction can take a lot more heat than the other internal components.

Measuring the hot side of the trans line will tell you the converter output temp, which might be important to you, but I would think that knowing the temp of what the more vulnerable parts are seeing is more valuable information.

That all being said, I would say I probably push these things as hard as anyone bracket racing a turbo car on a full tree. I end up being “on the converter” for a LONG time sometimes trying to get the turbo to spool, and chasing most people I race, which builds a LOT of heat. Aside from the first pass or two, my trans is NEVER UNDER 200 degree’s (pan measurement).

The ONLY time I’ve ever had an issue is a few years back when I was running a trans blanket. I think it was 2014’ish? At monster mopar in Norwalk I went to the last 3 cars in the 10’oh shootout, and the last 7 in pro. It was like NASCAR hot lapping the thing, and finally with the temps continuing at 300 degree’s pass after pass, the front pump seal finally gave up the ghost.

Since then, I switched to a carbon shield, and deeper pan. Now it usually runs around 250-275 degree’s on hot lap situations, and it’s never hurt a part. Is it ideal? Probably not. Do you guys need to keep your trans around 180 degrees? Probably not either.