Hyundai Repair: 97 Sonata (v6) 2-3/ 3-4 shift flares, transmission fluid change, excess fluid

Question
I've noticed if I let the car warm up to complete operating temperature, my shift flares are almost non-existent. If the engine is cold...it will continue to flare until it gets to operating temperature AND/OR I turn the engine off for a couple of hours. It has over 200k miles and is the only complaint I have about this vehicle. I'm the original owner. I'm writing because this morning, I let the vehicle warm up as usual. When I was changing lanes and increasing the throttle this morning and I could feel it bog and then stumble into 3rd and as soon as I came to a stop, I noticed that this time with engine warmed, unlike any other times, the flare was still there. But not each and every shift. It was intermittent. Even more shocking...I came to a stop in the garage to enter, proceeded to 1st gear and then 2nd gear and up a hill and I was concerned it would flare, but did not. I have recently (2 weeks ago) performed a transmission fluid change (not a flush) and I have noticed this more frequently. I got the car hot, put in all gears, then neutral and checked my fluid. It is WAY over the full mark with fluid up the dipstick. I always buy the Hyundai ATF and take about 6 qts with me to a quik lube type place. They usually return one or two to me since the car retains a good 5 quarts. This time, I forgot to ask about the other quarts...i think they have them all in there. Could this excess of fluid be causing the flare issue to aggravate itself?

Answer
The excess fluid could be a contributing factor.  To check, you'll need to drain the transmission back down to the proper level.  Most likely, there's a serious problem with the transmission, and you'll need to replace or overhaul it if you intend on continuing to drive this vehicle.