So I have a 1991 U1250. I know that it has the 8 speed gearbox with the splitter engaging between fourth and fifth. The issue I have is that I'm missing first and second gear. I know this since I can only engage two gears before the splitter kicks in and then I go through the final four gears. The other issue is that it doesn't like to stay in fifth and sixth gear which is essentially first and second. It never really seems to slide in; I have to hold it there. I want to know if this is a problem with the linkage or if it could be a lot worse? How would I diagnose this?