will parts from a john deere 850 work on a john deere 4100
Agree with kennyd,
The next model up from the 850 was the 870. The next model up from the 970 was the 4300..
The 4100's were not in the same line-up.. the previous model to the 4100 was the 670.
But checking part no's in jdparts as suggested would be the best route to go.