Well my gr2100 has a problem with the PTO/transmission. Had a grinding sound whenever mower was engaged. Dealer says the PTO shaft is whobbling and could have possibly damaged the transmission. I know about the warranty extension; however, mine has 450 hours which under the 500 but I am over on the 4 years by 2 months. He indicated Kubota may be willing to "work" with me on this but I am not counting on it. Has anyone had this happen and did Kubota help you? If not, what did it cost you to get it fixed?