Hi, I have a 2021 buck 450 that would pop out of gear when you put it in gear and hit the gas. couldn't get any help from massimo or the place I bought it from. Cant find a service manual for it, pulled off the seat and there two cables going to the trans from your gear shift left one is for low, right one is for high and reverse . I used a 3/4 inch wrench to loosen and tighten . adjustable wrench to keep the cable from spinning, lengthened the left cable about 1/4" and it stays in low and doesn't pop out or grind anymore, never had any problems with high and reverse. If anyone knows where you can get a service manual it would be great, hope this helps
John