Kubota M6950 Transmission Problems

[grofarms]

I have a Kubota M6950 which has been a great tractor on the farm and we love it and has never let me down until yesterday. It only has about 3000 original hours which is nothing for a Kubota. I went to use it yesterday and the A and B range in the transmission work great but when i put it in the C or D range it seems like its stuck in 2 gears. The tractor just bogs down and dies and don't move. It almost sounds like its something in the shift linkage or the shift forks but i'm not completely sure about how the guts work on the range part of the transmission. Is there a common failure in these transmissions or does anyone have and suggestions from past experiences?