Grand Caravan V6-3.8L VIN L (2007)
Overdrive Solenoid: Description and Operation
40TE Automatic Transaxle
Description
DESCRIPTION
Figure 1 Solenoid/Pressure Switch Assembly
The Solenoid/Pressure Switch Assembly (1) (Figure 1) is external to the transaxle and mounted to the transaxle case. The assembly consists of four
solenoids that control hydraulic pressure to the LR/CC, 2/4, OD, and UD friction elements. The reverse clutch is controlled by line pressure from the
manual valve in the valve body. The solenoids are contained within the Solenoid/Pressure Switch Assembly, and can only be serviced by replacing the
assembly.
The solenoid assembly also contains pressure switches that monitor and send hydraulic circuit information to the PCM/TCM. Likewise, the pressure
switches can only be service by replacing the assembly.
Operation
OPERATION
SOLENOIDS
The solenoids receive electrical power from the Transmission Control Relay through a single wire. The PCM/TCM energizes or operates the solenoids
individually by grounding the return wire of the solenoid needed. When a solenoid is energized, the solenoid valve shifts, and a fluid passage is opened
or closed (vented or applied), depending on its default operating state. The result is an apply or release of a frictional element.
The 2/4 and UD solenoids are normally applied, which by design allow fluid to pass through in their relaxed or "off" state. This allows transaxle limp-in
(P,R,N,2) in the event of an electrical failure.
The continuity of the solenoids and circuits are periodically tested. Each solenoid is turned on or off depending on its current state. An inductive spike