Notes: R212797-P.O.57203040 I.S.C.DIFF.SUPPORT 397972 is original JOHN-DEERE product. R212797-P.O.57203040 I.S.C.DIFF.SUPPORT 3979721 is commonly used in transmissions/axles/engines . if you have any questions please do not hesitate to contact us via Whatsapp +17275652849