Overdrive Range - Third Gear

Overdrive Range - Third Gear:

OVERDRIVE RANGE - THIRD GEAR

As vehicle speed increases and operating conditions become appropriate, the PCM energizes 2-3 shift solenoid to shift the transaxle into Third gear. The manual valve remains in the Overdrive (D) position and line pressure continues to feed the drive and PRND4 fluid circuits.

DIRECT CLUTCH APPLIES

2-3 Shift Solenoid: The normally open shift solenoid is energized by the PCM and blocks 2-3 signal fluid from exhausting. 2-3 Signal fluid pressure is routed to both the 1-2 and 2-3 shift valves.

2-3 Shift Valve: 2-3 Signal fluid pressure moves the valve against spring force to initiate the 2-3 upshift. 2-3 drive fluid is routed through the valve and into the 3-4 drive fluid circuit.

#5 Checkball (Direct Clutch Apply): 3-4 drive fluid pressure seats the #5 checkball and 3-4 drive fluid is forced through the #26 orifice and into the direct clutch feed fluid circuit. The #26 orifice helps control the direct clutch apply.

Direct Clutch: Direct clutch fluid pressure applies the direct clutch and the transaxle shifts into Third gear.

3-4 Shift Valve: 3-4 drive fluid is also routed to the 3-4 shift valve in preparation for a 3-4 upshift.


SHIFT ACCUMULATION

2-3 Accumulator: Direct clutch feed fluid is also routed to the 2-3 accumulator piston. This fluid pressure moves the piston against spring force and 2-3 accumulator feed fluid pressure. This action absorbs initial direct clutch fluid pressure to cushion the direct clutch apply. The movement of the 2-3 accumulator piston forces some accumulator fluid out of the accumulator.

2-3 Accumulator Valve: Excess 2-3 accumulator feed fluid is routed back to the 2-3 accumulator valve. This fluid pressure moves the accumulator valve against spring force and torque signal fluid pressure to regulate the exhaust of excess accumulator fluid. This regulation provides additional control for the direct clutch apply. The figure shows the exhaust of accumulator fluid during the shift by the arrow directions in the accumulator fluid circuit.

Note: The 2-3 accumulator fluid circuit does not include a checkball. However the checkball pocket is included in the channel plate casting.

Torque Converter Clutch: Under normal operating conditions the Torque Converter Clutch (TCC) is released in Third gear. However, TCC apply could vary depending on vehicle application and may be calibrated to apply in Overdrive Range - Third Gear.

Pressure Switch Assembly: Release fluid pressure routed to the Pressure Switch Assembly (PSA) signals the PCM that the TCC is released.