I've had a similar situation with my Kubota B2650 tractor, where I noticed an odd noise coming from the transmission. It wasn't exactly clacking, more of a grinding sound, but it turned out to be a bearing issue within the transmission assembly.
After some research and troubleshooting, I realized it was beyond a simple DIY fix. I ended up taking it to a
Kubota official dealer for a thorough check and repair. The dealer confirmed the bearing problem, replaced it along with a few other worn parts inside the transmission, and conducted a full service to ensure everything was in top shape. The repair wasn't cheap, but it was worth it to get my tractor running smoothly again. The total repair cost, including parts and labor, came to around $1,500. This covered the bearing replacement and a comprehensive check-up of the entire transmission system to ensure everything else was in good condition.