MUFFLER 2666318 - Caterpillar

Illustration 1 g01998720
View of transmission hydraulic control
(1) Outlet tube
(2) Transmission main relief valve
(3) Clutch modulating valves
(4) Tubes
(5) Solenoids
(6) Inlet tube Transmission charging oil from the transmission charging section of the pump flows through inlet tube (6) to the transmission main relief valve (2). The transmission main relief valve (2) may be adjusted with a screw that is located behind the cover for the transmission control valves.Transmission charging oil is used in order to fill the clutches. Transmission charging oil is also used in order to shift the transmission. Some of this oil drops to the bottom of the housing in order to be scavenged, but most of the charging oil flows to the torque converter through outlet tube (1) in order to provide charging oil for the torque converter.Oil flows through tubes (4) to the clutches in the rear transmission planetary group. From the top to bottom in Illustration 1, the tubes supply oil to clutches seven, four, five, and six.The Transmission ECM energizes solenoids (3) for the seven clutch modulating valves (5) in order to control the clutch engagement of the transmission.The right hand row of clutch modulating valves (4) that are shown in Illustration 1 provide oil to the following clutches (top to bottom):
Seventh speed clutch
Fourth speed clutch
Fifth speed clutch
Sixth speed clutchThe left hand row of clutch modulating valves (4) that are shown in Illustration 1 provide oil to the following clutches (top to bottom):
First speed clutch
Third speed clutch
Second speed clutchThere are two sizes of clutch modulating valves (4). The first speed clutch and the second speed clutch have smaller clutch modulating valves (4), since these clutches require less oil. Clutch modulating valves (4) for the first speed clutch and for the second speed clutch operate the same way as the larger clutch modulating valves.