Spicer Tandem Drive Axles Service Manual D__R440, 460, 480, D_R461, 462, 463, 521, 581, 601, 651, 652, 653 - Manual (Page 141)

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Theory of Operation
Theor
y of Operation
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.
Description and Operation
The Planetary Double Reduction Tandem Axle shares its basic
design concepts and many components with the Dual Range
Tandem. The principle variation is the permanent engagement
of the double reduction feature. A stationary sun gear, fixed in
engagement with the low-speed clutch plate, replaces the
sliding clutch gear and provides continuous double reduction
operation in the same manner as the dual range axle when in
Low Range.
Torque distribution and power flow is same as Dual Range
Gearing in Low Range.
Forward Axle Shift Unit
Rear Axle Shift Unit
Planetary Double Reduction Gearing
1 - First Reduction: pinion and ring gear
2 - Second Reduction: planetary gearing
2
1