I'm pretty sure you haven't hurt anything in this short amount of time.
It got up to somewhere around 280-300 (dunno exactly) for maybe 5-10 minutes on the hot line the other day. Actually I think it got that got that hot in the one lane construction zone, cooled down a little then got hot again going up a steep hill at low speed (25-30ish) after having to start off from a complete stop and stop and go leading up to it. Then it was just 2-3 minutes, if that. It felt like forever though. No place to stop so I had no choice.
Mostly it stayed at 220 max in stop and go or on curvey back roads with frequent braking and accelerating.
Out on the interstate, it mostly stayed cooler (180-200ish) except for a couple hills where it got up to 220ish or a bit higher. Keeping in mind that's the uncooled line coming out of the trans.
I reckon the 11 miles will be fine. I'll just baby the throttle so maybe getting up to speed won't generate as much heat. It's going to be cooler next Thursday too (65F or so) when I leave, so that may help a little. It was 75ish the other day.
I'll have about 50-60 miles after i flip the cooler to see if temps are any lower, or at least drop faster, before the cargo trailer and RV gets loaded up with lots more cargo from the storage unit.
If the temp still doesn't look good in stop and go, I may just go ahead and flush the radiator cooler myself and tie it in, transmission warranty be ****ed, if he decides to be that way about it. Once I'm on my way in a few weeks, I won't really have much warranty recourse anyway, unless he pays another shop to cover repairs under his warranty. But since he didn't R&R, I'd be on the hook for that if it's not something in the valve body or elsewhere that can be reached without pulling it.
And if there's damage, well, maybe it'll still last a good many years, just not as long as it should.