I have a 2003 Malibu, we don't have an owners manual and I needed to know how much fluid the transmission needs after pan and filter replacement? And there's no dipstick to check the fluid so how do you know if you have added the right amount?

Pan drop and filter change is about 7 quarts. With engine running and transmission oil at least 104 F pull the check plug to see if fluid comes out, replace plug before stopping engine or you will have a mess.
Vehicle needs to be level.