Just crank it up and drive- - - -the cooler is on the same circuit as lubrication pressure to the trans, so it's self-purging. Check the fluid level once it's warm- - -you might need to add a small amount to bring it back up to "full", but don't overfill the trans. The fluid grows quite a bit as it heats up.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!