Spicer Tandem Drive Axles Service Manual D__R440, 460, 480, D_R461, 462, 463, 521, 581, 601, 651, 652, 653 - Manual (Page 118)

114
Dual Range Axle Shift Systems
Standard System for Axle Range Selection
and Inter-Axle Differential Lockout
(straight air type)
Description
The standard dual range shift system consists of:
1. A manually-operated, air shifter valve to change axle
range.
2. A quick release valve which provides for fast release
of air pressure from the axle shift units.
3. Two air shift units mounted on the axles. These shift
units are mechanically connected to the axle shift
forks and sliding clutches which, in turn, shift axles
into Low or High Range.
For vehicles not equipped with automatic safety brakes, an ig-
nition-controlled solenoid valve exhausts the system and
downshifts the axles when the ignition switch is turned off. The
electrical circuit is protected by a circuit breaker.
1 - Circuit breaker †‡
2 - Speedometer adapter†
3 - Air pressure
4 - Axle range shifter valve (open in high
range)
5 - Solenoid valve‡ (exhaust system
when de-energized)
6 - Inter-axle differential lockout shifter
7 - Air pressure 8 - Forward axle shift unit
9 - Inter-axle differential lockout cylinder
10 - Rear axle shift unit
11 - Ignition switch†‡
12 - Pressure switch† (normally closed)
13 - Exhaust
14 - Quick release valve
15 - Dry air tank
16 - Air pressure with axle in high range,
inter-axle differential engaged † Pressure switch and speedometer
adapter required for vehicles with trans-
mission drive speedometers.
‡ Solenoid valve required for vehicles not
equipped with automatic safety brakes.