All-Wheel-Drive In Gu Chassis (If Equipped) - Mack Granite GU Series Operator's Handbook Manual

236 OPERATION
Do NOT (under any circumstances) engage or disengage the lockout while the
drive wheels are actually slipping or spinning; clashing between the lockout sliding
clutch and the outer cam may result.

All-Wheel-Drive in GU Chassis (If Equipped)

Transfer Case — The TC15 Series and TC25 Series are two-speed transfer
cases designed for all-wheel-drive vehicles. All gears are in constant mesh
and are of the helical type (for quiet running). All shafts and the differential
are mounted in heavy-duty tapered roller bearings. HI-LO engagement is
effected by means of a sliding clutch. A conventional fork spans the sliding
clutch and moves in response to movement of the gearshift hand-control
lever or air-control valve.
A planetary gear-type center differential is incorporated to provide
front-wheel-drive availability at all times (without requiring driver attention).
However, for extremely slippery conditions, a power divider lockout is provided.
WARNING
Do NOT attempt to shift between HI and LO range (or engage the transfer
case lockout) while the vehicle is in motion; drivetrain component damage
could occur.
Note: A transfer case NEUTRAL position is required when a transfer case power
take-off (PTO) unit is incorporated.