Weird transmission event I don't quite understand.

[TYYYYLER]

Hello!

I'm gonna list all the stuff leading up to today over the past 2 or 3 weeks before I describe what happened with my transmission, in case any of it is relevant.

I have a 1994 4.0 L V6 automatic 2wd Ranger. It has 150k miles and I'm not sure about the maintenance it has undergone in the past. About 3 weeks ago I changed the transmission fluid and filter because I thought I was going to tow my friends wrecked car to her house. Never did tow it though. I drove it for a day with low fluid after the change on accident, it would slip out of gear occasionally. Finally got it topped off the next day and no more problems.

Fast forward to last Sunday, me and 2 friends were going to go camping so I had the truck loaded with gear and people. I live in Phoenix AZ and it was a pretty hot day. The highway we were on was uphill in the desert (I17 through Black Canyon City if your familiar with the area). There was an accident on the freeway and this caused us to travel less than 3 mph for about an hour. This was causing my truck to run hotter than normal, about the midpoint on the temp gauge the whole time. I finally got off the road at the next exit and my truck was steaming a little.
I have a small coolant leak so I'm gonna guess that is why she got hot so fast and steamed a little. After I let it cool off she started up but was running rough and looked like some misfiring. The misfiring went away after a few minutes and the engine was running fine, but now it was slipping out of gear every couple of minutes. I limped the truck maybe 2 miles to an auto parts store and filled up the ATF. it took 2 quarts of fluid to fill it up. (I checked all my fluids that morning before we left and it was indeed full).
After I was filled up and everything looked good I got back on the freeway and I started smoking really bad, so I pulled over and found a pool of ATF about the size of my hand on the ground. It was leaking onto the exhaust and making smoke. I then drove home 45 miles with no problems after that. The leak did not come from the pan gasket I replaced a few weeks ago.
I've driven about 3 or 4 hundred miles since this happened, frequently checking my ATF fluid and it has stayed constant at a good level(not full but not low).

So my two questions are:
Could over heating have caused my transmission to somehow go through 2 quarts of fluid?

Why did I have a short lived leak after filling up with the 2 new quarts of ATF but then it stopped and hasn't leaked any more since? Could I have put just a little too much in and it somehow purged the excess fluid?

Sorry for the wall of text, I just want to be as thurough as possible with my explanation.
Thanks!

 

[Syritis]

yes. automatics are quite finicky about when to check them. some trans are checked hot and some are checked cold. immediately after start up. I haven't read though my manual yet so i wouldn't know for sure. but my guess is it's just over flow.

 

[shortzt]

Check your manual on how to fill if you got it too full it will come out the vent but usually it'll still be too full after you it blows out the vent, if its too full it will froath and create air bubbles and pockets and air is compressible, so when it goes to shift it won't get full pressure on the piston or it'll take longer for the fluid to build up to create the pressure

 

[TYYYYLER]

It's checked in park running. I didn't know there was a vent tube. I guess that would explain the leak after I filled it.

 

[shortzt]

It's usually just a button style vent on the top of the trans