I'm continuing to learn about this car so I apologize if I am posting something that others may have posted years ago.
The ATF on the stick (1997 4L60e) looked good and the gasket is not leaking so I decided just to suck the ATF out of the pan thru the dipstick tube and then replace a similar amount.
After reading about the shallow pan I expected to be able to pump out about 4.5 qts. I was only able to get 2.5 so I started looking at pictures of the inside of the transmission.
There is a dipstick stop that also stops any tube you put down the dipstick tube, so you can't get most of the ATF out of the pan with a pump. AND - it was evidently overfilled as I put back 1.5 and now it is at the top of the cross hatch area when hot.

 

Okay? Was the engine running when you checked the fluid level?

 

I recall sucking a similar amount out of a 2002 4l60e. Dropped the pan and there was barely another qt in it.

Do the suck and fill method 5-10 more times and it’ll be mostly fresh fluid. Be sure to run the engine between each suck and fill. Also Move the shifter through the gears. Forward, reverse.

 

Thanks for the reply and yes I checked it hot when idling in park. I've checked it after the last ten or so long drives since changing it and it is right at the top of the hash when hot. I'm a retired engineer/licensed mechanic and the purpose of my post was just to let those that might not be aware of the dipstick stop that it is there.