Description And Operation: 8F30: Notes

The 8F30 transmission is an eight speed electronically controlled transmission. The transmission assembly a unique transmission oil to hydraulically actuate the elements needed for each gear range. Input torque is provided by a torque converter that drives the input shaft and the mechanical oil pump that supplies hydraulic pressure to actuate the clutches. The torque converter also has an electronically modulated Torque Converter Clutch (TCC) to reduce slippage, generated heat, and increase efficiency when conditions warrant. The transmission also has an Electric Oil Pump (EOP) mounted externally to the case to support Engine Stop Start (ESS) functionality. During the restart event the EOP supplies hydraulic pressure to allow the transmission to respond almost immediately to launch the vehicle. The transmission contains a differential assembly that allows for output torque to exit the transmission at different speeds to the left and right halfshafts. The transmission also has a provision for mounting the Power Transfer Unit to the right side of the differential housing. The transmission provides input torque to the PTU to allow for AWD or 4WD operation.

The Transmission Control Module (TCM) is bolted to the exterior of the transmission case, above the differential. The TCM directly controls solenoids located on the valve body to automatically upshift and downshift, control line pressure and the Torque Converter Clutch (TCC). The TCM uses direct inputs from the transmission such as the input and output speeds, transmission oil temperature, the Transmission Range Switch (TRS) as well as indirect inputs other modules to control when and how the transmission shifts. The TCM also monitors the various inputs and outputs for proper operation and reports DTCs when a failure is detected.