PLATE A 4B8845 - Caterpillar

Shifting the Transmission to the FIRST SPEED FORWARD position
Illustration 2 g06013260
Transmission hydraulic control in the FIRST SPEED FORWARD position and with the engine running.
(1) Transmission hydraulic control relief valve
(2) Torque converter
(3) Torque converter outlet relief valve (if equipped)
(4) Transmission oil filter
(5) Modulating valve for the Number 1 clutch
(6) Modulating valve for the Number 4 clutch
(7) Modulating valve for the Number 2 clutch
(8) Modulating valve for the Number 5 clutch
(9) Modulating valve for the Number 3 clutch
(10) Modulating valve for the Number 6 clutch
(11) Transmission oil pump
(12) Torque converter inlet relief valve
(13) Suction screen and magnet
(14) Oil sump
(15) Transmission lubrication
(16) Oil cooler
(17) ECM
(G) Number 1 clutch pressure tap
(H) Number 4 clutch pressure tap
(J) Number 2 clutch pressure tap
(K) Number 5 clutch pressure tap
(L) Number 3 clutch pressure tap
(M) Number 6 clutch pressure tapThe power train electronic control module (ECM) modulates the electrical current that is sent to the selected modulating valves. Modulating the current to the modulating valve controls the transmission clutch pressure.When the transmission direction and speed control lever (if equipped) are moved to the FIRST SPEED FORWARD position, both Number 2 clutch solenoid (7) and Number 6 clutch solenoid (10) are energized. When the transmission direction control switch (if equipped) and the transmission upshift switch are shifted to the FIRST SPEED FORWARD position, both Number 2 clutch solenoid (7) and Number 6 clutch solenoid (10) are energized.Number 2 clutch solenoid (7) is electronically modulated when the Number 2 clutch is filled. Number 6 clutch solenoid (10) is electronically modulated when the Number 6 clutch is filled. When the electrical current is modulated to the full current, the Number 6 clutch and the Number 2 clutch are at full oil pressure.Modulating valves (5), (6), (8), and (9) are not energized. The leakage oil drains to oil sump (14).Transmission in the FOURTH SPEED REVERSE position
Illustration 3 g06013267The power train electronic control module (ECM) modulates the electrical current that is sent to the selected modulating valves. Modulating the current to the modulating valve controls the transmission clutch pressure.When the transmission direction and speed control lever (if equipped) are moved to the FOURTH SPEED REVERSE position, both Number 5 clutch solenoid (8) and Number 1 clutch solenoid (5) are energized. When the transmission direction control switch (if equipped) and the transmission upshift switch is shifted to the SECOND SPEED REVERSE position, both Number 1 clutch solenoid (5) and Number 5 clutch solenoid (8) are energized.Number 1 clutch solenoid (5) is electronically modulated when the Number 1 clutch is filled. Number 3 clutch solenoid (9) is electronically modulated when the Number 3 clutch is filled. When the electrical current is modulated to the full current, the Number 5 clutch and the Number 1 clutch are at full oil pressure.Modulating valves (6), (7), (8), and (10) are not energized. The leakage oil drains to oil sump (14).Single Clutch Speed Shifting
Illustration 4 g02825938
Conventional speed shift logic
Illustration 5 g02825956
Single clutch speed shift logic
(A) Clutch pressure
(B) Time
(1) On-coming speed clutch
(2) Off-going speed clutch
(3) Directional clutchThree clutches are involved during a