INTER-AXLE DIFFERENTIAL LOCK
Inter-axle differentials serve the same purpose between front and rear axles of tandem drive units as they do in single
axle drives except that it permits one axle, instead of one wheel to rotate faster or slower than the other. This is necessary
because when turning corners or operating on uneven terrain, the wheels on the two axles in the tandem assembly are
going at different speeds. This would also occur if tires were mismatched by wear or size, between the front and rear
By LOCK OUT of the inter-axle differential, both axles are forced to turn at the same speed regardless of slippage on
one axle, thus delivering power to the axle that does have traction.
IMPORTANT: SHIFT TO LOCK POSITION ONLY WHEN AXLES ARE MOVING AT SAME APPROXIMATE SPEED OR
WHEN AXLES ARE COMPLETELY STOPPED.
FAILURE TO DO THIS WILL CAUSE TREMENDOUS
INSTANTANEOUS STRAIN ON THE GEARS AND SHIFTING COLLAR RESULTING IN SERIOUS DAMAGE. WHEN
SHIFTING TO UNLOCK, RELEASE THROTTLE SUFFICIENTLY TO REDUCE TORQUE TO THE DRIVE TRAIN TO A
Simple rules to remember in operation of the use of the Inter-Axle Differential Lock are:
Use UNLOCK with good traction and favorable operating conditions.
Use LOCK with poor traction and unfavorable operating conditions.