Spicer Drive Axle Wheel Differential Lock - Manual (Page 8)

6
Overview
Transmission Low-Range Interlock System
The wheel differential is locked manually with the transmission in Low-Range.
It is unlocked by the driver or unlocked when the transmission is shifted out of
Low-Range. It is designed to ensure the differential lock is not left engaged at
speeds above 25 mph.
When the driver places the cab mounted control valve in the lock position and
with the assist pressure from the transmission control circuit, tank air pres-
sure is supplied to the differential lock shift unit through the cab mounted
control valve.
Note: If the transmission is shifted out of low range (with cab mounted con-
trol valve in the lock position), the air pressure to the differential shift
units is shut off automatically. The transmission Low-Range valve
closes, shutting off air assist supply to the cab mounted control valve
which, in turn, releases the tank air pressure from the air shift unit. If the
driver subsequently shifts back into Low-Range, the differential lock will
not re-engage automatically.
In-Cab Switch
or Valve
Transmission -
Low-Range