COIL AS-FIELD 9W0059 - Caterpillar

Illustration 1 g01115525
Transmission Hydraulic Control
(1) Main Relief Valve
(2) Port for No. 3 Clutch
(3) Port for No. 2 Clutch
(4) Port for No. 1 Clutch
(5) Port for No. 5 Clutch
(6) Port for No. 4 Clutch
(7) Modulating Valve for No. 4 Clutch
(8) Transmission Output Speed Sensors
(9) Modulating Valve for No. 5 Clutch
(10) Modulating Valve for No. 1 Clutch
(11) Modulating Valve for No. 2 Clutch
(12) Modulating Valve for No. 3 Clutch The transmission hydraulic control contains the main relief valve and the five modulating valves for the transmission clutches. The transmission hydraulic control is mounted on the top of the transmission.Oil from the transmission charging section of the power train oil pump passes through the transmission charge filter to the transmission hydraulic control.The five modulating valves control the flow of this oil to the transmission clutches. Main relief valve (1) maintains the maximum pressure that is available to the transmission clutches and the brake control valve. Also, main relief valve (1) protects from pressure spikes.Transmission Modulating Valves
Illustration 2 g01261745
Transmission Modulating Valve
(13) Solenoid
(14) Ball
(15) Orifice
(17) Valve Spool
(18) Spring
(19) Oil From Transmission Charging Section "C"
(20) Passage to Clutch
(21) Drain
(22) Pin
(BB) Cutaway Section
(CC) Component Surface
(FF) Activated Component
(GG) Tank Pressure
(JJ) High Pressure
(KK) First Pressure Reduction Each clutch is controlled by a transmission modulating valve. Solenoid (13) is energized in order to engage the corresponding clutch.The modulating valve allows the respective clutch to fill with oil to a pressure that is determined by the amount of current going to the solenoid. The power train ECM determines the amount of current that is supplied to the solenoid.The amount of current that is supplied to the solenoid is determined by the response of the machine, which includes the following indicators:
Speed sensors
Gear selection
Oil temperatureAs current is applied to the solenoid, pin (22) extends to the right. The pin moves ball (14) closer to orifice (15). The ball restricts the amount of oil to drain (21). This increases the pressure on the left end of valve spool (17).As the pressure at the left end of the spool increases, the spool shifts to the right. Pump oil is now directed to the clutch through passage (20). When the clutch fills, pressure begins to increase and the clutch engages.As clutch pressure increases, the pressure plus the force of spring (18) move the spool back to the left. When maximum clutch pressure is reached, a balance is maintained between clutch pressure and solenoid (13). The spool is in a metering position.De-energizing the solenoid returns pin (22) to the left. The pressure on the left end of the spool forces the ball away from the orifice. Pressure on the left end of the spool drains through drain (21). This allows the spool to shift to the left. Clutch pressure is now directed to the drain and the clutch is disengaged.Main Relief Valve
Illustration 3 g01215899
Main Relief Valve
(19) Oil From Transmission Charging Section "C"
(23) Adjustment Screw
(24) Spring
(25) Spool
(26) Slug Chamber
(27) Slug
(28) Passage to Transmission Hydraulic Control
(29) Passage to Power Train Lube Circuit
(BB) Cutaway Section
(CC) Component Surface
(FF) Activated Components
(GG) Tank Pressure
(HH)