TM 5-3805-296-23-1
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STEERING AND SCRAPER HYDRAULICS CONTINUED
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Secondary Steering Gear Pump
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The secondary steering gear pump mounts to the front of the differential and is gear driven by the ring gear of the
differential. The secondary steering gear pump only operates when the wheels are turning forward. The secondary
steering gear pump consists of a small section and a large section. When the machine is moving forward, the oil
output from the small section of the secondary steering gear pump supplements the oil output from the steering
section of the hydraulic and steering pump.
Output from the secondary steering gear pump is controlled by a valve spool which is turned off by pilot pressure
from the hydraulic and steering pump. When engine RPM decreases below a sufficient speed or the engine stops,
pilot oil from the steering and hydraulic pump decreases opening the spool valve. Output oil from the large section
of the secondary steering gear pump then flows to the steering control valve.
If the machine moves backward or is not moving at all, the secondary steering gear pump will not operate. When
the machine moves backward or stops moving and the hydraulic and steering pump fails, the machine cannot be
steered.
Figure 6. Steering System.
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