Transmission not shifting

I have been having issues for over a year now so I'm pretty sure the transmission isn't failing (fingers crossed). It started with a second-third shift flare (which at the time I thought was slipping). Over about a 3 month period the second-third flare got longer/worse always present and the other shifts between gears developed a flare but only intermittent. By the way this flaring only happened when I got on the gas slowly or normal driving. If I got on the throttle hard then there was no flaring at all between shifts. At this point in time I proceeded to do 3 drain and fills with Honda ATF with no noticeable change at all with the shifting. I then replaced solenoids (shift, linear and TCC lockup)which seemed to eliminate the flaring but now there is a shuttering feeling between first-second shift and sometimes while just driving without shifting. I have been doing more research and I'm thinking that the torque converter could possibly be my next culprit. My main question is, could it take over a year for the converter to slowly fail or would it be quicker than that? Is there a way to test the torque converter?