Chapter 12 Electronic Control Systems 299 Copyright by Goodheart-Willcox Co., Inc. First Gear Hydraulic Flow – D, D Range Reverse clutch Inter clutch Forward clutch Direct clutch Manual low relief 1XX 1XX BB B2 B9 L34 K PRNDL D OD D L DL Pump Manual Pump Filter Sump P HH Conv. reg. sol. reg. Pump UU BB AA B1 TT L234 KK Bypass cl sol VFS TV sol. P1 L34XX 1XX Q BBB P2 2-3 shift OD D L P2 DCX L234 B6 LISR T B10 SF P1 Sol. #1 OFF (N.O.) Sol. #2 ON (N.O.) Sol. #3 OFF (N.O.) P3 P2 DD Rear B3 Rel. Apply L/I servo OD D L 2-3 servo reg. GG Engagement LISA P2′ Pull-in 3-2 shift timing DCX L Pump Fwd. clutch control P3 LFC 3-4 shift J OD D L Int. clutch shuttle R ICEX P2′ 1-2 shift M L L3 L234 L34XX FC Rev L4 Rev L 12 L LL DCEX P2 PP LISR LI2X L234 L12 L Rev L12 B5 DL B F B11 L34XX ICEX L12 S E L12X TV VFS L L4 Pressure failsafe Backout E V (opt) Accum. reg U ZZ FF MM Pump NN (opt) LFC C Int. cl L234 VV Y CC PC Main reg. TV Rev CPY L Z Bypass clutch control C-BY 1-2 cap mod. 12 acc. L4 B4 H O.D. servo N-D accum. X L12X 3-4 accum. ODSA 1-2 accum. Converter C-BY CT CI W F. lube Cooler Converter drain back YY Diff. = Line = Pump control = TV = Converter feed, Case lube = Accumulator charge A Rev Figure 12-42. The oil flow schematic of an electronically controlled, four-speed, front-wheel drive transaxle. The transaxle is in the overdrive range, first gear, and the engine is running. Study the components in this schematic before proceeding. (Ford) an additional solenoid. This solenoid is used to apply the converter lockup clutch, and operates independently of the overdrive solenoid. The lockup clutch can be applied in third or fourth gears. In Figure 12-46, governor pressure on one end of the 2-3 shift valve has overcome throttle pressure on the other end and moved the 2-3 shift valve to the upshifted position. The transmission is now in third gear, which is direct drive (1:1). Movement of the shift valve allows fluid into the direct (front) clutch apply piston and intermediate (front) servo release chamber. This same oil pressure is also delivered to the 3-4 shift and 3-4 timing valves. However, the oil going to the 3-4 shift valve must pass through a restricting orifice, and leaks out DCX L4S L24 L234 L12 Rev L3 L4 CT CL