How many drain plugs did you remove for draining? There are 2. One is on right side near lower draft link, and the other is further forward and in the center of the case. Probably should be between 7 and 8 gallons. Also I was thinking about your pto problem. Can you feel 2 stages as you push in the pedal? There are 2 styles of pedals on 2020 depending on serial number. one has 2 holes in pedal where adjustable link connects. If you have 2 holes, install the adjustable link in the hole furthest from the pivot pin. If you have the single hole version, there is an adjustable bracket that limits how far the pedal comes up in the released position. Make sure to loosen the bolt in the bracket and then pull the pedal back as far as it will go. this is proper position for dual stage clutch. tighten bolt in this position. If you can post pictures, I can help determine if it is correct if my description is not clear.