Hello, My name is XXXXX XXXXX I will gladly assist you with your vehicle concern.
O.K. First off... wow! Congrats on 292,000 miles.
Now, I am betting you had a catalytic converter inefficiency code. Not uncommon, especially with the miles on the car. To verify this, a temp reading is taken at the front "inlet" of the cat and the rear "outlet" of the cat. If the temp is not 100 deg hotter on the outlet, the cat is not "reacting" properly and is bad.This test is done at 3000 rpm for 3 minutes before the temp reading is taken. A laser thermometer is used.
Now, the trans, what you describe is the seals going hard over time and age. As the trans fluid heats up, it will make the seals more pliable; thus reducing fluid bypass and able to increase pressure for shifting.
If the fluid quality is poor, a Transmission flush using the recommended trans fluid is recommended With the miles on the trans, and i am assuming it is original, you did good, but this is a Hail Mary pass at best.
sounds good. thanks for the info