How to check transmission fluid level

[RangerGene]

1991 Ford Ranger V-6, 4.0L: I have read the manual eight times but I am still not sure I have the proper amount of fluid . Checking it cold, without the engine running (is it supposed to be running when you check it cold?) the level is just below the hatchmarks on the dipstick; fluid covers both of the holes on the dipstick. Checking it after driving on the freeway for 25 miles, with the engine running, the dipstick is clean, no trace of fluid. I let it cool down for 30 minutes, checked it again (engine off), fluid reaches the bottom hole on the dipstick.
I am not comfortable with the dipstick being "clean" after the freeway driving. Please HELP !

THANKS !

 

[pcollins]

read the dipstick. it is supossed to be checked idling in park, when hot, so it is BAD that the dipstick is clean after driving. add fluid while its running and keep checking it while its hot until it reaches the top of the crosshatches. from bottom of hatch to top takes one pint of fluid.

 

[RangerGene]

Thanks for the advice. Here is the back story: a while back, the truck was serviced at a garage. Sometime after that, I checked the fluid level (after a 25 mile drive on the freeway); it read really high. Truck was shutoff for 4 hours. Drove it back home (25 miles on the freeway); still read really high, way up from the top of the hatchmarked area. Soooooooooo, and this is where I must have gone sideways, I assumed too much fluid was in the reservoir. So I removed about 1.5 qts of fluid (so stupid). Having re-read the manual now, it specifically states that after freeway or hot day driving, let the vehicle rest for about 30 minutes prior to checking. I put fluid back in yesterday.
Question now is: have I done permanent damage to the transmission or do I get a pass on this blunder? Drove it around 200 miles or less on the LOW fluid.