Hello have a 2000 Hyundai Tiburon 2 litre.

Hello have a 2000 Hyundai Tiburon 2 litre Automatic. I recently replaced the Transmission and Torque Converter ( something came lose within the transmission and shot through the housing/ torque converter was replaced the torque converter because I wasnt sure if they was a fracture in it) also replaced the Transmission Seal. The problem I am having is when it automatically switches gears while im driving for example speeding up it will gear up but when it does that there is a knock, or a bang, This bang happens when it both gears down and up.

It seems to be worse in the morning when the car has sat for hours and is still cold, when the engine heats up and the temp is at the right degree everything seems to be fine, might happen a few times but not near as much as it does while cold. Non the less I dont think this should be happening at all and I dont want a problem to occur out of this so I thought id look into it.