Was bush hogging a week ago and was attempting to back up, which I had done successfully several times just a bit earlier. Put the shifter in reverse and eased out on the clutch but noticed I didn't feel any engagement as I let the clutch partially out. I moved shift lever to park and then back to reverse and I eased the clutch completely out this time, but tractor didn't move. I shifted to park and eased the clutch out but tractor tried to move forward, and I could hear some gear grinding. Also, I can't get shifter to move left across center neutral position to go to high or low. I haven't looked under the cab floor plate yet. Is this a linkage problem or internal to the transmission? Of note, this is a factory T/A delete tractor. Thanks in advance for any responses.