304 Automatic Transmissions and Transaxles Copyright by Goodheart-Willcox Co., Inc. Screen Rear clutch Rear servo Front clutch Front servo Accumulator Overdrive clutch 3-4 accumulator 3-4 shuttle valve 3-4 timing valve 3-4 shift valve Overdrv sol Lockup sol Lockup valve Lockup timing valve Selector lever in drive overdrive gear T/C unlocked Front clutch lubrication L/U switch valve Cooler To lubrication Torque converter Oil filter Pump Screen Regulator valve Manual valve 1-2 shift valve Governor plug Throttle plug Throttle plug Limit valve Governor plug 2-3 shift valve Governor valve Oil pressures Line 57-94 PSI Governor 0-57 PSI Converter/lube 5-57 PSI Throttle 0-94 PSI 1-2 Shift control 25-70 PSI Pump suction Throttle valve Kickdown valve 1-2 shift control valve Shuttle valve 7 9 4 3 6 8 1 2 5 Figure 12-47. Fourth gear of a transmission with partial electronic shift control is achieved when the overdrive solenoid is de-energized. Compare the solenoids, shift valves, and oil circuitry with those in Figure 12-45. (Chrysler) Primary limit valve Calibrated orifice Primary feed limit Drive pulley Fixed portion of pulley Sliding portion of pulley Variable ratio control A solenoid or electric motor can be used to adjust the variable ratio control valve Figure 12-48. Moving the control valve varies hydraulic pressure to the drive pulley piston. Changes in the hydraulic pressure applied to the drive pulley piston causes one side of the drive pulley to move toward or away from the fixed side, changing the effec- tive diameter of the drive pulley.