I uploaded that pic of a root from my phone and copied the wrong link.
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Had to take her apart to investigate the drive problem, it wasn't too bad to get the motors out. I didn't have to mess with any of the hydraulics or electrical. (Well, disconnected two motor wires. )
After pulling the motor I found this was the problem, in the video you can see when it breaks. I don't think anything was binding I think it may have been locked onto a root and just the power of the motor broke the sprocket. And I did not have that second set screw in there where the fracture occurred.
I do have two 11 tooth sprockets. The sprockets on now are 9. I did want a bit more speed for reversing and I have them so I think I will try them. They are the shiney ones in the above pic. A lot more meat on them. Only thing I have to do is make a new motor shaft as the small ones are 1/4" and the others are about 3/8". I still have the clearance for chain and everything else. Next time I dig up some bigger roots I will snip them with hand shears. I know this is a beast but it's not indestructible. We may even till up the track so roots will not be an issue.