Interaxle Differential Locks and Automatic Traction Control Systems can be your best friends if you use them correctly and at the right time. What are they and how do you use them?
The Interaxle Differential Lock mechanically locks the front and rear axles together so both have equal amounts of power delivered to each axle. Why is that important? Every twin drive axle tractor has three differentials which allow the wheels to turn at different speeds. This improves steering control and reduces tire wear during normal operation on dry pavement. When you are on a slippery surface and one wheel has less traction than the others, it is possible for all of the power to go to one wheel even if the other three wheels have good traction. The result will be that one wheel will spin while the others just sit there. When you turn on the Interaxle Differential Lock switch, it mechanically locks the front and rear drive shafts together which will result in at least two of the four wheels having to turn. That at a minimum doubles the chances of having traction to move forward. Let's say that you have the Interaxle Differential Lock engaged and you have two wheels spinning because of lack of traction. In that case, there is another system that will aid in distributing the power evenly to all wheels. It is the Automatic Traction Control System.
The Automatic Traction Control System monitors wheel spin and lightly engages the brake on the wheels that are spinning so that the power will be diverted to the wheels that have traction. When the system is working, you will feel kind of a shuffle of the rear tires when you are on a slippery surface as the ATC system diverts power to the wheels with greater traction. When using this system, it is important not to over speed the driveline, but rather move along slowly so that it can do its job. The system limits the RPM and torque so that the operator doesn't over speed and break traction. Inevitably, there will be a scenario where the buld up of snow is too great and it will help to increase the speed and/or torque to be able to move. In that rare case, there is an ATC system over-ride switch that will turn off the traction control system momentarily to allow for increased RPM and torque.
So what is the best practice? If you are in an off-road environment that is slippery, lock your Interaxle Differential Lock so that you gain the advantage of that system. Make sure you turn off your Interaxle DIfferential Lock when you are on the road. Allow your Automatic Traction Control System to do its job. Only engage the ATC over-ride as a last resort, realizing it can only help if the tires are able to bite into the snow. It will not aid you on ice.
Is there ever a time when you should use the Interaxle Differential Lock system over the road? Yes. If the roads are very slippery and you are traveling at significantly reduced speeds, but make sure that any time you turn on your Interaxle Differential Lock you are stopped. The Interaxle Differential lock collar can be severely damaged, destroying the entire front differential assembly if engaged while the input and outpout shafts are turning at different speeds. If you learn how to work with these friends they will help you to get your job done safely with greatly minimized risk of getting stuck.