I changed the transmission fluid yesterday in my 2014 Mustang GT with the 6R80 trans. It went pretty smoothly. I put all four wheels up on ramps and still barely had room to get under the car. Prior to today, I had bought an extra Ford tranny pan and had a drain plug welded in and had also installed the Performance Automatic dipstick kit. I had also bought a huge drain pan that was big enough to cover the entire size of the pan so any messes were kept to a minimum. My car only had a little over 31,000 miles but I wanted to change it early based on FordTechMakuloco's recommendations in his Youtube video. I only got out about 5.75 quarts of fluid and that is with dumping the filter out and I ended up putting in 6 and it was right at the full mark on the PA dipstick. PA recommends only filling it up to about half way into the cross hatch area of their dipstick even though they say anywhere in the cross hatch is okay. I've left the fluid alone but may drain some out to get it to the halfway mark. The car shifts fine and seems slightly smoother than before. I let it idle for awhile and then took it for a drive to make sure the internal thermostat would be open when I checked the level. I used the Motorcraft Mercon LV and the correct Motorcraft filter. The dipstick made filling the tranny easier but kind of slow since occasionally the fluid would back up in the funnel and "burp" fluid out so you had to make sure you kept something to put over the funnel handy to avoid making a mess. All in all it went pretty smoothly and the old fluid wasn't that bad looking.
Here are some pictures of the pan with the drain plug welded in. I had this done before Dorman came out with a pan for this transmission that has the drain plug in it.
Here are some pictures of the pan with the drain plug welded in. I had this done before Dorman came out with a pan for this transmission that has the drain plug in it.