gettin ready to get a used TCI from a close friend....was too loose for his setup....and he mentioned something about gettin it flushed before i install it......anyone know anything about this or if there's anything else i need to do or know? thx guys

 

Flushing is a waste of time IMO.
If the trans it came off of had a failure you will need to get it cut open and rebuilt. If you don't you run the risk of ruining your trans with the debris trapped inside.
If it was working fine just turn it upside down in a bucket and let it drain or just install it.