Good evening, I have a 1950 John Deere B (SN 267148) and it has developed a "clunk" in the transmission. It only happens when in gears on the right side, 1st, 2nd, 4th and reverse. The noise speeds up and slows down with tractor speed. I have blocked the back of the tractor up and put it in gear, held one wheel in place while I rotated the other wheel, can feel and here it in the transmission. Has anyone had any experience with this? I have removed the inspection plate and looked for broken tooth but haven't found anything yet. If you any direction to point me towards to get started I would appreciate it.