2005 camry xle v6 shudders

Hi guys, thanks to Eric for his video , i now understand how the transmission works
I have a 2005 Camry xle v6 . purchased in Dec 2014, mint. 108,000 Km
In May of 2017 , was at at red light , raining , went to apply gas, and the car shuddered. i reapplied gas and was fine.
I asked my Toyota service manager about it , said we’d need to do a diagnostic , but could be a fluke. worked fine so i did nothing
In Aug 2019 also at a red light in rain , went to apply gas ,and car sorta lurched 3 times. reapplied gas was ok.
From what i saw from Eric’s video is the torque converter, could be suspect.
Car is now at 160,000 Km , i asked for a transmission fluid change last fall Nov 2018 , was told i’d be wasting my money ,because fluid looked
like new , no different from new fluid

can a diagnostic be done, or do they simply have to take apart to find out. I read somewhere there may be solenoids in the transmission as well
it would appear that when this happens the vehicle is about to stall. and by taking my foot of the gas , and reapplying somehow resets it
The Camry is known to be pretty reliable, and i have no info on what was done prior to my purchase