It is the diff-lock actuator pin, the linkage is not adjusted correct, After mine was toook back to dealer & adjusted it has been fine ever since, but do not drive it anymore & have your dealer adjust it. The pin is not coming out far enough, mine comes out about 3/8 to 1/2" farther than when I 1st got it. Also get a copy of the fix & the sypmtoms for the warraty work order, that way if you are covered in the future after warraty expires, simply because this is a factory mistake & not the dealers fault,It would be easy to do yourself, but definatley let the dealer do it. It will not do it anymore once adjustment is made.. JD should be made awhere of this problem so every one is covered on this simple but potentially bad resulting problem. please keep us updated on this. I like the design of this tractor, very comfortable for long hrs in the seat, I have done 8hrs shots @ a beat up 42& felt no pain. Loader is smooth, everything is smooth. I have had it is deep clay & it made iteven with r4's. The loader is strong enough toflip that tractor even w/ loaded tires, so be carefull.Lotsa USA built parts on it if you look. Do not drive it anymore till it is fixed..bummer, but it is a new series, so somebugs will have to be worked out. I have about 100hrs on mine & it has earned it's keep & not lookingto trade up.
Joe