Spicer Tandem Drive Axle Dual Range & Double Planetary 34,000-45,000 lbs - Manual (Page 4)

Spicer ¬ Dual Range Tandem Drive Axles
Description and Operation
Spicer Dual Range Tandems are
basically 2-Speed, shiftable drive
axles. They provide two gearing
ratios (low and high ranges) and
are designed for heavy-duty service
in on-off highway operations. Low
range for deep gear reduction and
slow speed hauling off highway.
High range for cruising speeds on
highway.
The complete tandem axle
assembly includes two axle units,
each with double gear reduction
capability coupled by a 2-gear S PICER Dual Range Gearing
power divider. with Lube Pump
Power Divider
In operation, the power divider accepts the torque from the vehicle
drivelne and distributes it equally to the two axles.
This assembly is of the two-gear design consisting of an input shaft,
inter-axle differential, output shaft and two constant-mesh helical
gears.
The inter-axle differential compensates for axle speed variations in the
same way the wheel differential works between the two wheels of a
single drive axle. This unit also acts as a central point in distribution
of torque to the two axles.
The power divider also includes a driver-controlled, air-operated
lockout. When lockout is engaged, it mechanically prevents inter-axle
differentiation for better performance under poor traction conditions.
Lube Pump
Tandem Axles with suffix letter "P" in Model No. are equipped with a
lube pump to provide positive lubrication to the inter-axle differential
and other power divider parts. This pump is operated by a drive gear
engaged with the input shaft splines. When vehicle is moving in a
forward direction, pressurized lube is delivered to the vital power
divider parts.
Lube Pump System
The pump lube system
incorporates a magnetic strainer
screen. To keep the system clean,
the magnet traps minute particles
and the screen blocks out large
particles of foreign material.
Dual Range Tandem Shift System
Range selection is accomplished
by an air shift system and is driver-
controlled through a cab-mounted
air control valve.
The control valve operates two
shift units (one for each axle)
which mechanically engages or
disengages the planetary gearing.
For operation description, refer
to Shift System section in this
manual.
Forward Axle Rear Ax/e
Shift Unit Shift Unit
4