Automatic Transmissions confuse me.

[bgkast]

I've been working on changing my '85s ATF and filter for the better part of two months now (not working very hard mind you ) and have a question.

The owners manual states to check the ATF level with the engine idling in park, and that when the fluid is cold it should be a bit below the "low" mark. I added fluid to below the mark, drove the car a little, then let it sit for a few weeks.

Today I checked the fluid level again before I used the car (after letting the engine idle in park for a few minuets) and the fluid level was almost at the bottom of the stick. “Great....I must have a leak” I thought, so I added another half a quart of Mobil 1 ATF. After I got home from driving with everything nice and hot, and the engine running in park I checked the fluid level again and it is about 1/2" above the high mark.

What gives? What is the fluid volume between the low and high marks on the '85 transmission? Should I use hot fluid or cold as my bench mark?

Thank you.