There have been a few that had a defect in a molding seam when the tank was made, but that usually shows up in a short time after the tractor is purchased. If yours is a 2020 it would be odd for it to start leaking after this much time, but anything is possible. It could have a crack. I saw one that had a cotter pin on the mower deck lift linkage poke into the tank when the hitch and deck were raised all the way up. Check the fuel hose and clamp that are attached at the bottom of the tank also..
There is no pto speed knob, but the hitch drop speed knob and mower deck height adjuster knob have to be removed. The drop speed knob has a screw recessed in the center of it. The mower deck height knob has a roll pin through the shaft that has to be driven out with a hammer and punch. It helps to have someone hold a big hammer against the shaft so it doesn't just bounce while you drive out the pin. The rubber grips on the control levers can be hard to get off. I put the jaws of a needle nose pliers on the lever below the grip and pull up on the jaws and handle of the pliers at the same time like a T handle. They are usually stuck and hard to pull off if they have never been removed before.
