Spicer Tandem Drive Axle Dual Range & Double Planetary 34,000-45,000 lbs - Manual (Page 59)

Dual Range Axle Shift Systems
There are two shift system designs predominantly used to
select range of an Spicer dual range tandem axle.
1. Standard System.
For range selection, a cab-mounted air
shifter valve operates two air shift units mounted on the axles.
The inter-axle differential lockout is of the straight-air type
and air-operated to engage lockout and spring-released to
disengage lockout.
2. Axle Range Interlock System.
This system has an added
feature to prevent axle shifting when the inter-axle differential
is locked out. The axle range air shifter valve for this system
includes an Interlock Pin Assembly to provide the interlock
feature.
The inter-axle differential lockout is of the straight-air type. It
is equipped with an Interlock Control Valve which controls
air pressure delivery to the shifter valve Interlock Pin,
Detailed information on these systems is included in this
manual.
“Reverse-Air” Type Inter-axle Differential Lockout.
Some
shift systems may include this lockout design. It is spring-
operated to engage or “Lock” the differential and air-operated
to disengage or “Unlock” the differential.
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