New Temperature Switch and Solenoid Wiring Harness

SUBJECT:

New Temperature Switch And Solenoid Wiring Harness
TRANSMISSION APPLICATIONS:

1987 THM 700-R4 (MD8)
TRANSMISSION MODELS:

FAM, MAM, MDM, MFM, MKM, MLM, MMM, MPM, MRM, MVM, MWM, MXM, MZM, TJM, TKM, TVM, TXM


VEHICLE APPLICATION:

M-Van with: 4.3L engine G-Van with: 4.3L, 5.0L, 5.7L engine R, V, C and K Truck with: 4.3L, 5.0L, 5.7L engine

Figure 29 - Type 15 Wiring Diagram:

CHANGE TO ASSEMBLY COMPONENTS:

^ New temperature switch and bracket assembly (Figure 29), page 26

^ New solenoid and wiring harness assembly (Type 15, Figure 29)
DATE OF CHANGE:

July 17, 1986, Julian Date 198, for 1987 THM 700-R4 transmission models as listed above. The equivalent 1987 Service Replacement Transmission Assembly (SRTA) models have the new temperature switch and solenoid wiring harness.


SERVICE ACTION:

The new temperature switch is designed to prevent the transmission from overheating by applying the torque converter clutch (TCC) under certain conditions. With the gear selector in D and the transmission operating in 4th gear, the temperature switch is normally open. If the transmission is operating in 4th gear without TCC apply and the fluid temperature reaches 126~ - 135~C (259~ - 275~F) the switch closes. When closed, the [1][2]torque converter clutch is applied to allow the fluid to cool to 106~ - 119~C (222~ - 246~F), when the switch opens and normal TCC operation resumes.

The new temperature switch is mounted to the control valve assembly by an existing bolt and can be serviced by removing the transmission oil pan.
SERVICE PARTS INFORMATION:

Part Number Descriptions

8654421 Temperature Switch (1987 models as listed)

8654415 Solenoid Assembly Complete (1987 models as listed)