904 doesn’t seem to have second gear?

Ok so my 904 transmission last year started to not go into gears and seemed to slip. I may have overfilled the transmission fluid. I let it sit for the winter and it leaked fluid and when I brought it back out it started going back into gear but would take a while before it kicked in. I dropped the pan and the filter was pretty nasty so I changed it and it goes into gear good now. Only problem is it doesn’t seem like it has 2nd gear. It goes in first and when you accelerate there isn’t a noticeable jump from first to third but you can only hear it shift once. When you manually put it in 2nd it just revs up and seems like it’s slipping. It won’t downshift into second either when you are going 60 but will downshift into first if you are going slower and punch it. Not sure what the problem is or how to fix it. Is it possible for it to have completely worn 2nd gear? Let me know

Also before I changed the filter and oil it was making a loud buzz and vibration sound when it went into reverse.