Clunking noise appears to be coming from L/H drive train to transmission. Notable when starting to move, even on smooth roads. Intensifies with distance. Transmission replaced.
When the trans was replaced were the drive axles checked for free play in the CV joints?
Also check suspension ball joints and bushings.
You may have a ball joint that is on it’s way out.
It is common for them to make a clunk when changing direction.