TM 5-3805-298-23-1
0004
BRAKING AND HYDRAULIC FAN SYSTEM CONTINUED
To increase air flow, the transmission ECM decreases electric current to the demand fan solenoid valve causing
the demand fan solenoid valve to close. When the demand fan solenoid valve closes, pilot pressure at the flow
control valve increases causing the flow control valve to close. As the flow control valve closes, hydraulic oil from
the braking and hydraulic fan pump must now flow through the fan motor thus increasing fan speed.
To decrease air flow, the transmission ECM increases electric current to the demand fan solenoid valve causing
the demand fan solenoid valve to open. When the demand fan solenoid valve opens, pilot pressure at the flow con-
trol valve decreases causing the flow control valve to open. As the flow control valve opens, hydraulic oil from the
braking and hydraulic fan pump now flows through the flow control valve instead of the fan motor thus decreasing
fan speed.
The hydraulic oil flows from the fan motor to the hydraulic oil cooler. From the hydraulic oil cooler, the hydraulic oil
flows through the hydraulic oil filter to the hydraulic oil tank. If the hydraulic oil cooler is restricted or plugged, the oil
bypasses the oil cooler and returns to the hydraulic tank.
END OF WORK PACKAGE
0004-8
