Reference
( 1 ) Perform Rear Differential Lock Operational Check
Action:
Set engine speed to low idle. Drive tractor straight forward at slow or moderate speed.
Engage differential lock pedal and turn steering sharply in either direction.
Tractor should have tendency to go straight forward, or cause inside rear tire to slip.
Release differential lock pedal and tap brake pedal or stop and reverse direction briefly, if necessary, to release differential lock.
Test steering again by steering sharply in either direction. Steering should return to normal.
Result:
YES: Rear differential lock is operating properly. Go to next check.
NO: Return to diagnosis in progress.