When To Use 4wd On Your Yanmar Tractor

The short answer: "only when you need it".

The Longer Answer:
4wd locks your front differential and rear differential together. There is no 'slip' in this system. It is a positive mechanical lock. This is great for getting better traction but can also be very hard on the drivetrain if used incorrectly.

The problem arises when the front tires and rear tires and not in perfect ratio so that they travel the same distance with each revolution of the transmission. In reality, this almost never happens because just a little extra wear on one tire or even differences in tire pressure can put this ratio of of balance. The result is one axle is trying to travel farther with each revolution that the other. This can out a enormous strain on the 4wd system.... especially if you are going fast or driving on a surface with good traction.

 Pro Tips:
- Do not ever use 4wd when you don't need it. The tires must be able to slightly slip off the slight travel distance per revolution of the tire.

 - Do not ever change the tire size on one axle without also changing the other axle's size to maintain the correct ratio. 

 - Do not force the 4wd shift lever. If it seems like it is in a bind try rolling forward or backward or steering in a circle while applying slight pressure on the shift lever. 

 - Do not ever engage 4wd while you are moving. Come to a complete stop before shifting.