Torque converter, can it cause hesitation at slow speed gear changes?

if the trans was tested correctly, then the torque converter was checked also. yes you can put it on a computer scanner. not a code puller but a real scan tool that will read what the trans is doing while you are driving. it sounds like it is slipping before shifts. I think you have an internal issue. let a trans shop check it correctly for you and give you a bid. Roy