I recently purchased a GT14 with power shift. It has a slight leak in the differential and I want to add fluid but I'm not sure what to add. I have not received my owners manual yet. ?Can anyone help out?? I also have a starter which can get finicky. I have to tap on it every once in a while to get it to turn over. Any help here? Other than that I like the machine just fine. Runs well and has a lot of power for 14HP.