2011 4.0 4x4 overdrive going out on long trips

I have a 2011 Toyota Tacoma I purchased in September 2018 with just under 81k miles. I have had no issues with the truck until I took a 5 hour trip to visit friends.

The truck was fine on the way down (because I stopped for lunch) but on the way home (after 4 hours of driving) I passed a car and noticed my overdrive went out and my RPM were between 3000-3500 while traveling 65-70mph. I turned it off for an hour or two and drove it home with no issues. I took it to the dealer that week to check the transmission fluid and it was 2 quarts low. After they filled it back up I haven't had any issues. 102k miles (Feb 2021)

This past weekend I did a lot of driving around town and put 250 miles on my truck in one day. When coming home on the interstate I had the cruise set and had to turn it off to slow down a time or two to get around some cars. When I tried to turn the cruise back on it wouldn't work and I noticed my RPM was around 3000 going 60-65mph, so I pulled over on the next road I saw and turned the truck off for a minute or two. When I got back in the truck it was back to normal and I drove it home an hour like that. I took it to the dealer today to get the transmission fluid checked again and it was half a quart low. (Feb-Mar 2022)

Has anyone had any similar issues or do you know what may be causing it? The truck runs and drives fine 99% of the time but I hardly ever take it on long trips or drive it that much in 1 day so that's why I never noticed anything until now.

TIA

 

And you don’t notice any leaks at all when you’re under the truck looking around?

 

No, I haven't noticed any leaks nor did the technician but I'm going to let it run awhile and check it again this afternoon

 

ANY issue goin back to the computer will Null Out cruise control

by example .......a loose or non compatible gas cap will
throw codes & null the cruise control

check levels on ALL the fluids of Ur truck.............ALL !!! ( NO mention in Ur post U checked !!)