Overdrive light blinking / 2000 Ford Windstar

This is another one of my posts about THE SAME VAN! could the problems mentioned be the cause of the blinking light!
I have a 2000 windstar that was leaking tranny fluid. Ford says it’s the torque converter seal BUT recommends that I also replace the converter the same time as the seal. Is this really necessary?
Would this cause the van to make a ‘kind of’ clunking noise when it comes to a stop?
I asked them if the tranny was “sound” other than the leak they said yes. Is there a certain test I should ask them to perform to know for sure?
THANKS!