Back story is yesterday I changed radiator, fan clutch , and thermostat. Noticed when I drove the truck the transmission seamed to be slipping a little. This morning leaving for work slipped again so I decided to check the fluid thinking more may have leaked out than I thought. Well it was low so I added about 1/2 to 3/4 of a quart. Slipping seams to have stopped but a miss started. Could be a big coincident but now I am concerned about the fluid level.

I just checked it again after sitting at work for 4 hours. The dipstick has a plastic end with add at the bottom, then a crisscrossed area with cold, then a larger crisscrossed area hot, and then do not add.

So with the truck sitting as it is the fluid is at the top or add or bottom of cold however you want to read it.

I am confused should I add more fluid or drive it and check it hot and running?

 

It must be checked hot and running, in Park. Bring it up to the do not add mark.

 

From your description of the levels, the trans was not below level for running.
Slipping should not have occurred as long as you could see any fluid on the dip stick.
Same with crank case oil level. The Low mark does not mean out of oil. It mean don't let it go any longer or you will be out of oil at the wrong time and lose the motor.
The stick marking have a built in safety level.
Same is true with the cooling system. There is tolerance built in looking at the coolant level marking on the jug.
This is common sense territory.
Good luck.