In total the transmission in a Toyota Tacoma takes 6 quarts of transmission fluid.
That is 2 quarts of transmission fluid are in the torque converter and another 4 quarts of transmission fluid go into the transmission pan.
But if you only drain the transmission fluid in the transmission pan then you would only need 4 quarts of transmission fluid to refill the transmission pan.
When adding the transmission fluid add 2 quarts of transmission fluid and then start the engine up to let the transmission fluid flow through the transmission then as it's idling add the other quart of transmission fluid and then add the last 4th quart of transmission fluid to the transmission.
Just add it slowly so you do not overfill the transmission as it can mess the transmission up but you should be safe with 4 quarts of transmission fluid added to the transmission of the Toyota Tacoma.