The torque converter should really shift the car ahead with just a light contact with the accelerator pedal. Change between the opposite gears (Drive and Sport, For those who have it) to check out if you can hear every other Appears from it. If every thing seems to be fine, https://torque-converter-clutch42963.thezenweb.com/the-basic-principles-of-torque-converter-clutch-72019684