Automatic Transaxle Overhaul - 4T40-E/4T45-E: Other Saturn ION I

Final Drive Pinion End Play Check

1. Inspect the end play with a feeler gauge for proper clearance. Proper clearance is 0.24-0.62 mm (0.009-0.024 in).
2. If the clearance is out of specification on the low side, repair the differential assembly as necessary.
3. If the clearance is out of specification on the high side, replace the differential assembly (116).

Fretting Ring, Final Drive Internal Gear Install

1. If the fretting ring (119) has been removed, install the fretting ring (119) into the small groove in the transmission case (51).
2. Install the final drive internal gear (118) into the transmission case (51).

Forward Clutch Support, Low Roller Clutch Install

1. Install the forward clutch support and lo roller clutch assembly (114) into the transmission case. Compress the parking pawl spring, and line up the parking pawl with the parking pawl gear.
2. Install the forward clutch support snap ring (112) into the transmission case with the chamfer side up. Use a screwdriver in order to set the snap ring into place.

Input Carrier Pinion Gear Clearance Check

1. Measure the pinion gear end play for proper clearance. Use a feeler gage. The clearance should be 0.24-0.69 mm (0.01-0.027 in).
2. Inspect the reaction internal gear and the input carrier assembly for damage or excessive wear. Specifically inspect the condition of the pinion gears, the washers, and the thrust bearings.
3. Clean and dry each of the components.

Reaction Carrier Pinion Clearance Check

1. Measure the reaction carrier pinion gear end play for proper clearance. Use a feeler gauge. The clearance is 0.24-0.69 mm (0.01-0.027 in).
2. Clean and dry each of the components.

Direct and Coast Clutch Functional Air Checks

1. Air check the direct clutch in order to verify the proper operation of the seals and clutch assembly.
2. Air check the coast clutch in order to verify the proper operation of the seals and clutch assembly.

Scheme 193

Install the direct/coast clutch and reaction carrier assembly (105) into the transmission case (51).

Reverse Clutch Functional Air Check

Tools Required

J 41235 Second Roller Clutch Installer. See Special Tools .

1. Air check the reverse clutch in order to verify the proper operation of the seals and clutch assembly.
2. Assemble the 2nd roller clutch assembly (452) into the roller clutch cam (451).
3. While rotating the roller clutch in order to properly engage the rollers, assemble the 2nd roller clutch onto the reverse clutch housing (454).
4. Assemble a new 2nd roller clutch retainer (450) onto the 2nd roller clutch assembly. Use the J 41235 in order to press the retainer and roller clutch assembly into place on the reverse clutch housing and roller clutch inner race. See «Special Tools»(ref-200504-S20398696432005102000000) .
5. Hold the reverse clutch housing, and ensure that the roller clutch cam rotates clockwise only.

Park or Neutral - Engine Running (W/o Electronic Range Select Mode)

When the gear selector lever is in the Park (P) position and the engine is running, fluid is drawn into the oil pump. Line pressure is directed to the pressure regulator valve.

Pressure Regulator Valve

The pressure regulator valve regulates the pump output (line pressure) in response to a torque signal fluid pressure, which acts on the boost valve, the spring force, and the line pressure acting on the end of the valve. Line pressure is directed to the manual valve, to both accumulator valves, to the torque signal regulator valve, to the TCC regulated apply valve, to the temperature sensor in the Automatic Transmission Fluid Pressure Manual Valve Position Switch (TFP Val. Position Sw.), and to the actuator feed limit valve. Also, line pressure feeds the converter feed fluid circuit through the pressure regulator valve.

Actuator Feed Limit (AFL) Valve

Line pressure is routed through the valve and into the actuator feed fluid circuit. The valve limits the actuator feed fluid pressure to a maximum pressure. Actuator feed fluid is routed to the pressure control solenoid and to each of the shift valves. The fluid also feeds the 1-2 signal and the 2-3 signal fluid circuits.

Pressure Control Solenoid (PCS) Valve

Controlled by the PCM, the PCS valve regulates the filtered actuator feed fluid pressure which acts on the end of the torque signal regulating valve.

Manual Valve

The gear selector lever mechanically controls the manual valve, which is in Park (P) position. The manual valve directs line pressure into the PRND4 and the PRN fluid circuits.

1-2 Shift Solenoid Valve

Energized by the PCM, the normally open 1-2 shift solenoid valve is On and blocks the 1-2 signal fluid from exhausting. The 1-2 signal fluid pressure acts on the 1-2 and the 3-4 shift valves.

1-2 Shift Valve

The 1-2 signal fluid pressure holds the valve in the downshifted position against a spring force. Low/PRN fluid is routed through the 1-2 shift valve and into the Low band fluid circuit.

Low and Reverse Servo

Low band fluid is routed to the inner area of the servo piston. Low band fluid pressure moves the servo piston and pin assembly against a spring force in order to apply the low/reverse band.

2-3 Shift Solenoid Valve

The normally open 2-3 shift solenoid is Off and the 2-3 signal fluid is exhausted through the solenoid.

2-3 Shift Valve

A spring force holds the 2-3 shift valve in the downshifted position.

3-4 Shift Valve

The 1-2 signal fluid pressure holds the 3-4 shift valve against a spring force in the First and the Fourth gear positions.

Lube 2

The lube 2 fluid circuit is fed by line pressure at the pressure regulator valve. Lube 2 fluid is routed through the oil feed pipes and into the forward clutch support. Lube 2 fluid provides lubrication in the rear of the transmission.

1-2/3-4 Accumulator Valves

Line pressure is regulated into accumulator fluid pressure. Torque signal fluid pressure acting on the end of the valve basically controls this regulation.

Park or Neutral - Engine Running (With Electronic Range Select Mode)

When the gear selector lever is in the Park (P) position and the engine is running, fluid is drawn into the oil pump. Line pressure is directed to the pressure regulator valve.

The pressure regulator valve regulates the pump output (line pressure) in response to a torque signal fluid pressure, which acts on the boost valve, the spring force, and the line pressure acting on the end of the valve. Line pressure is directed to the manual valve, to both accumulator valves, to the torque signal regulator valve, to the TCC regulated apply valve, to the temperature sensor in the Automatic Transmission Fluid Pressure Manual Valve Position Switch (TFP Val. Position Sw.), and to the actuator feed limit valve. Also, line pressure feeds the converter feed fluid circuit through the pressure regulator valve.

Line pressure is routed through the valve and into the actuator feed fluid circuit. The valve limits the actuator feed fluid pressure to a maximum pressure. Actuator feed fluid is routed to the pressure control solenoid and to each of the shift valves. The fluid also feeds the 1-2 signal and the 2-3 signal fluid circuits.

Controlled by the PCM, the PCS valve regulates the filtered actuator feed fluid pressure which acts on the end of the torque signal regulating valve.

The gear selector lever mechanically controls the manual valve, which is in Park (P) position. The manual valve directs line pressure into the PRND4 and the PRN fluid circuits.

Energized by the PCM, the normally open 1-2 shift solenoid valve is On and blocks the 1-2 signal fluid from exhausting. The 1-2 signal fluid pressure acts on the 1-2 and the 3-4 shift valves.

The 1-2 signal fluid pressure holds the valve in the downshifted position against a spring force. Low/PRN fluid is routed through the 1-2 shift valve and into the Low band fluid circuit.

Low band fluid is routed to the inner area of the servo piston. Low band fluid pressure moves the servo piston and pin assembly against a spring force in order to apply the low/reverse band. The low band fluid is routed to the 3-4 shift valve. The pressure moves the valve against 1-2 signal fluid.

The normally open 2-3 shift solenoid is Off and the 2-3 signal fluid is exhausted through the solenoid.

A spring force holds the 2-3 shift valve in the downshifted position.

The 1-2 signal fluid pressure holds the 3-4 shift valve against a spring force in the First and the Fourth gear positions.

The lube 2 fluid circuit is fed by line pressure at the pressure regulator valve. Lube 2 fluid is routed through the oil feed pipes and into the forward clutch support. Lube 2 fluid provides lubrication in the rear of the transmission.

Line pressure is regulated into accumulator fluid pressure. Torque signal fluid pressure acting on the end of the valve basically controls this regulation.

When you move the gear selector lever from the Reverse position to the Neutral position, the following changes occur to the hydraulic and electrical systems.

The manual valve is moved to the Neutral position, where the valve blocks the line pressure from entering the Reverse fluid circuit. The reverse fluid circuit is opened to an exhaust at the manual valve.

Reverse Clutch

Reverse fluid exhausts from the reverse clutch and the clutch releases. This action shifts the transmission in to Neutral position.

Boost Valve

Reverse fluid exhausts from the boost valve and line pressure regulation returns to the normal operating range.

Low and Reverse Band Remains Applied

As in Park and Reverse positions, the solenoid valve is energized and 1-2 signal fluid pressure acts on the 1-2 shift valve.

The 1-2 signal fluid pressure keeps the 1-2 shift valve in the downshifted position. Low/PRN fluid continues to feed the low band fluid circuit.

Reverse fluid exhausts from the servo. However, low band fluid pressure continues to act on the inner area of the servo piston in order to keep the band applied.

Scheme 194

When you move the gear selector lever from the Reverse position to the Neutral position, the following changes occur to the hydraulic and electrical systems.

The manual valve is moved to the Neutral position, where the valve blocks the line pressure from entering the Reverse fluid circuit. The reverse fluid circuit is opened to an exhaust at the manual valve.

Reverse fluid exhausts from the reverse clutch and the clutch releases. This action shifts the transmission in to Neutral position.

Reverse fluid exhausts from the boost valve and line pressure regulation returns to the normal operating range.

As in Park and Reverse positions, the solenoid valve is energized and 1-2 signal fluid pressure acts on the 1-2 shift valve.

The 1-2 signal fluid pressure keeps the 1-2 shift valve in the downshifted position. Low/PRN fluid continues to feed the low band fluid circuit.

Reverse fluid exhausts from the servo. However, low band fluid pressure continues to act on the inner area of the servo piston in order to keep the band applied.

Scheme 195

Reverse (W/o Electronic Range Select Mode)

When you move the gear selector lever to the Reverse (R) position (from the Park position), the following changes occur in the transmission's hydraulic and electrical systems.

With the manual valve in the reverse position, line pressure is directed into the reverse fluid circuit, in addition to the PRND4 and the PRN fluid circuits, which were used in Park position.

Pressure Regulator and Boost Valves

Reverse fluid is routed to the boost valve. Reverse fluid assists torque signal fluid pressure. The addition of reverse fluid pressure increases the operating range of the line pressure in Reverse position.

Reverse clutch fluid pressure applies the reverse clutch.

The PCM keeps the solenoid valve energized in Reverse position. The 1-2 signal fluid pressure acts on the 1-2 shift valve.

The 1-2 signal fluid pressure keeps the 1-2 shift valve in the downshifted position. Low/PRN fluid continues to feed the low band fluid circuit.

Reverse fluid is routed to the outer area of the servo in order to increase the servo apply pressure in the Reverse position.

Pressure Regulator (PR) Valve

Line pressure is routed through the PR valve and into the converter feed fluid circuit. Converter feed fluid is routed to the TCC feed limit valve.

TCC Feed Limit Valve

Converter feed fluid is routed through the valve and into the TCC feed limit fluid circuit.

TCC Regulated Apply Valve

A spring force holds the valve in the release position, thereby blocking line pressure.

TCC Control Valve

A spring force holds the valve in the release position. TCC feed limit fluid is routed into the release fluid circuit. Fluid returns from the converter in the apply fluid circuit. This fluid is routed through the valve and into the cooler fluid circuit.

Lube 1

Cooler fluid is routed through the transmission oil cooler, which is located in the vehicle radiator, and into the lube 1 fluid circuit. Lube 1 fluid is routed through the input shaft in order to lubricate the transmission components in the front of the transmission.

The lube 2 fluid circuit is fed by line pressure at the pressure regulator valve. Lube 2 fluid is routed through the oil feed pipes and into the forward clutch support. Lube 2 fluid provides lubrication in the rear of the transmission. The lube 2 fluid circuit is fed by line pressure at the pressure regulator valve. Lube 2 fluid is routed through the oil feed pipes and into the forward clutch support. Lube 2 fluid provides lubrication in the rear of the transmission.

Scheme 196

Reverse (With Electronic Range Select Mode)

When you move the gear selector lever to the Reverse (R) position (from the Park position), the following changes occur in the transmission's hydraulic and electrical systems.

With the manual valve in the reverse position, line pressure is directed into the reverse fluid circuit, in addition to the PRND4 and the PRN fluid circuits, which were used in Park position.

Reverse fluid is routed to the boost valve. Reverse fluid assists torque signal fluid pressure. The addition of reverse fluid pressure increases the operating range of the line pressure in Reverse position.

Reverse clutch fluid pressure applies the reverse clutch.

The PCM keeps the solenoid valve energized in Reverse position. The 1-2 signal fluid pressure acts on the 1-2 shift valve.

The 1-2 signal fluid pressure keeps the 1-2 shift valve in the downshifted position. Low/PRN fluid continues to feed the low band fluid circuit.

Reverse fluid is routed to the outer area of the servo in order to increase the servo apply pressure in the Reverse position. The low band fluid is routed to the 3-4 shift valve. The pressure moves the 3-4 shift valve against the 1-2 signal fluid.

Line pressure is routed through the PR valve and into the converter feed fluid circuit. Converter feed fluid is routed to the TCC feed limit valve.

Converter feed fluid is routed through the valve and into the TCC feed limit fluid circuit.

A spring force holds the valve in the release position, thereby blocking line pressure.

A spring force holds the valve in the release position. TCC feed limit fluid is routed into the release fluid circuit. Fluid returns from the converter in the apply fluid circuit. This fluid is routed through the valve and into the cooler fluid circuit.

Cooler fluid is routed through the transmission oil cooler, which is located in the vehicle radiator, and into the lube 1 fluid circuit. Lube 1 fluid is routed through the input shaft in order to lubricate the transmission components in the front of the transmission.

The lube 2 fluid circuit is fed by line pressure at the pressure regulator valve. Lube 2 fluid is routed through the oil feed pipes and into the forward clutch support. Lube 2 fluid provides lubrication in the rear of the transmission. The lube 2 fluid circuit is fed by line pressure at the pressure regulator valve. Lube 2 fluid is routed through the oil feed pipes and into the forward clutch support. Lube 2 fluid provides lubrication in the rear of the transmission.

Scheme 197

Overdrive Range, First Gear (W/o Electronic Range Select Mode)

When you move the gear selector lever to the Overdrive (D) position from the Neutral (N) position, the following changes occur in order to shift the transmission into Overdrive Range - First Gear.

In the Overdrive position, the manual valve directs line pressure into the drive fluid circuit. The manual valve blocks line pressure from entering the PRN fluid circuit and the manual valve opens the PRN fluid circuit in order to exhaust.

Low band fluid pressure exhausts from the servo, releasing the servo and the low and reverse band.

Forward Clutch

Drive fluid is orificed into the forward clutch fluid circuit. Forward clutch fluid pressure applies the forward clutch.

In first gear, the PCM energizes the 1-2 shift solenoid valve and the 1-2 signal fluid pressure acts on the 1-2 shift valve.

The 1-2 signal fluid pressure keeps the 1-2 shift valve in the downshifted position against a spring force. Drive fluid is routed through the 1-2 shift valve.

Overdrive Range, First Gear (With Electronic Range Select Mode)

When you move the gear selector lever to the Overdrive (D) position from the Neutral (N) position, the following changes occur in order to shift the transmission into Overdrive Range - First Gear.

In the Overdrive position, the manual valve directs line pressure into the drive fluid circuit. The manual valve blocks line pressure from entering the PRN fluid circuit and the manual valve opens the PRN fluid circuit in order to exhaust.

Low band fluid pressure exhausts from the servo, releasing the servo and the low and reverse band.

Drive fluid is orificed into the forward clutch fluid circuit. Forward clutch fluid pressure applies the forward clutch.

In first gear, the PCM energizes the 1-2 shift solenoid valve and the 1-2 signal fluid pressure acts on the 1-2 shift valve.

The 1-2 signal fluid pressure keeps the 1-2 shift valve in the downshifted position against a spring force. Drive fluid is routed through the 1-2 shift valve.

Overdrive Range, Second Gear (W/o Electronic Range Select Mode)

As vehicle speed increases and operating conditions become appropriate, the PCM de-energizes the 1-2 shift solenoid valve in order to shift the transmission into Second gear. The manual valve remains in the Overdrive (D) position and line pressure is routed into the drive and PRND4 fluid circuits.

The normally open shift solenoid valve is de-energized and 1-2 signal fluid exhausts through the open valve.

With 1-2 signal fluid pressure exhausted, a spring force moves the valve into the upshifted position. Drive fluid is routed into the 2-3 drive fluid circuit. Drive fluid also continues to flow through the valve and to the A/T Fluid Pressure Manual Valve Position Switch.

#2 Checkball (Second Clutch Apply)

The 2-3 drive fluid seats the #2 checkball, forcing the 2-3 drive fluid through the #3 orifice and feeding the second clutch fluid circuit. The #3 and the #4 orifices help to control the apply feel of the second clutch.

Second Clutch

The second clutch fluid pressure applies the second clutch, which shifts the transmission into Second gear.

1-2 Accumulator

Second clutch fluid is also routed to the 1-2 accumulator piston. A combination of second clutch fluid pressure and the 1-2 assist spring force moves the piston against this spring force and the 1-2 accumulator feed fluid pressure. This action absorbs the initial second clutch fluid pressure in order to cushion the second clutch apply. The movement of the 1-2 accumulator piston forces some of the fluid out of the accumulator.

1-2 Accumulator Valve

The 1-2 accumulator feed fluid which is forced from the 1-2 accumulator unseats the #4 checkball. This fluid is then routed back to the 1-2 accumulator valve. This pressure forces the 1-2 accumulator valve against a combination of spring force and torque signal fluid pressure in order to regulate the exhaust of excess accumulator fluid. This regulation provides additional control for the second clutch apply.

TCC Control - Pulse Width Modulated (PWM) Solenoid Valve

Filtered 2-3 drive fluid is routed to the TCC control solenoid valve. Under normal operating conditions the TCC control solenoid valve is Off in Second gear. This valve blocks filtered 2-3 drive fluid from entering the TCC signal fluid circuit.

The 2-3 shift solenoid valve remains Off in Second gear, and the 2-3 signal fluid exhausts through the normally open solenoid valve.

A spring force keeps the 2-3 shift valve in the downshifted position. In this position the valve blocks 2-3 drive fluid, in preparation for the upshift into Third gear.

Scheme 198

Overdrive Range, Second Gear (With Electronic Range Select Mode)

As vehicle speed increases and operating conditions become appropriate, the PCM de-energizes the 1-2 shift solenoid valve in order to shift the transmission into Second gear. The manual valve remains in the Overdrive (D) position and line pressure is routed into the drive and PRND4 fluid circuits.

The normally open shift solenoid valve is de-energized and 1-2 signal fluid exhausts through the open valve.

With 1-2 signal fluid pressure exhausted, a spring force moves the valve into the upshifted position. Drive fluid is routed into the 2-3 drive fluid circuit. Drive fluid also continues to flow through the valve and to the A/T Fluid Pressure Manual Valve Position Switch.

The 2-3 drive fluid seats the #2 checkball, forcing the 2-3 drive fluid through the #3 orifice and feeding the second clutch fluid circuit. The #3 and the #4 orifices help to control the apply feel of the second clutch.

The second clutch fluid pressure applies the second clutch, which shifts the transmission into Second gear.

Second clutch fluid is also routed to the 1-2 accumulator piston. A combination of second clutch fluid pressure and the 1-2 assist spring force moves the piston against this spring force and the 1-2 accumulator feed fluid pressure. This action absorbs the initial second clutch fluid pressure in order to cushion the second clutch apply. The movement of the 1-2 accumulator piston forces some of the fluid out of the accumulator.

The 1-2 accumulator feed fluid which is forced from the 1-2 accumulator unseats the #4 checkball. This fluid is then routed back to the 1-2 accumulator valve. This pressure forces the 1-2 accumulator valve against a combination of spring force and torque signal fluid pressure in order to regulate the exhaust of excess accumulator fluid. This regulation provides additional control for the second clutch apply.

Filtered 2-3 drive fluid is routed to the TCC control solenoid valve. Under normal operating conditions the TCC control solenoid valve is Off in Second gear. This valve blocks filtered 2-3 drive fluid from entering the TCC signal fluid circuit.

The 2-3 shift solenoid valve remains Off in Second gear, and the 2-3 signal fluid exhausts through the normally open solenoid valve.

A spring force keeps the 2-3 shift valve in the downshifted position. In this position the valve blocks 2-3 drive fluid, in preparation for the upshift into Third gear.

Scheme 199

The PCM energizes the normally open 2-3 shift solenoid valve, which blocks the 2-3 signal fluid from exhausting. The 2-3 signal fluid pressure is routed to both of the 1-2 and 2-3 shift valves.

The 2-3 signal fluid pressure moves the valve against a spring force in order to initiate the 2-3 upshift. The 2-3 drive fluid is routed through the valve and into the 3-4 drive fluid circuit.

#5 Checkball (Direct Clutch Apply)

The 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 to control the direct clutch apply.

Direct Clutch

The direct clutch fluid pressure applies the direct clutch, causing the transmission to shifts into Third gear.

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

2-3 Accumulator

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

The PCM energizes the normally open 2-3 shift solenoid valve, which blocks the 2-3 signal fluid from exhausting. The 2-3 signal fluid pressure is routed to both of the 1-2 and 2-3 shift valves.

The 2-3 signal fluid pressure moves the valve against a spring force in order to initiate the 2-3 upshift. The 2-3 drive fluid is routed through the valve and into the 3-4 drive fluid circuit.

The 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 to control the direct clutch apply.

The direct clutch fluid pressure applies the direct clutch, causing the transmission to shifts into Third gear.

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

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

The PCM energizes the normally open 1-2 shift solenoid valve, which blocks the 1-2 signal fluid from exhausting. The 1-2 signal fluid pressure is routed to both the 1-2 and the 3-4 shift valves.

The 1-2 signal fluid pressure does not affect the 1-2 shift valve. A combination of spring force and the 2-3 signal fluid pressure keeps the 1-2 shift valve in the upshifted position.

The 1-2 signal fluid pressure moves the valve against a spring force and into the Fourth gear position. The 3-4 drive fluid is routed into the fourth band fluid circuit.

Intermediate and Fourth Servo

The 1-2 signal fluid pressure moves the valve against a spring force and into the Fourth gear position. The 3-4 drive fluid is routed into the fourth band fluid circuit.

3-4 Accumulator

The fourth band fluid is also routed to the 3-4 accumulator piston. Fourth band fluid pressure moves the piston against a combination of spring force and 3-4 accumulator feed fluid pressure. This action absorbs initial fourth band fluid pressure in order to cushion the intermediate and Fourth band apply. The movement of the 3-4 accumulator piston forces some fluid out of the accumulator.

3-4 Accumulator Valve

The 3-4 accumulator feed fluid which is forced from the 3-4 accumulator unseats the #7 checkball and the fluid is routed back to the 3-4 accumulator valve. This pressure forces the 1-2/3-4 accumulator valve against a combination of spring force and torque signal fluid pressure in order to regulate the exhaust of excess accumulator fluid. This regulation provides additional control for the intermediate and fourth band apply.

TCC Control Solenoid Valve

When conditions are appropriate, the PCM energized the TCC control solenoid valve in order to initiate the TCC apply. The solenoid valve is pulse width modulated (PWM) in order to provide a smooth TCC apply (Refer to the electrical controls section for a detailed description of the TCC control solenoid valve operation). When energized, the solenoid valve modulates the filtered 2-3 drive fluid into the TCC signal fluid circuit.

TCC Signal fluid pressure modulates the valve against a combination of spring force and TCC regulated apply fluid pressure. This action directs line pressure into the TCC regulated apply fluid circuit in relation to vehicle operating conditions.

Modulated TCC signal fluid pressure moves the valve against a spring force in relation to vehicle operating conditions. This action regulates TCC regulated apply fluid into the apply fluid circuit. At the same time, the release fluid circuit is opened to an orificed exhaust. In this position the valve directs TCC feed limit fluid in order to feed the cooler fluid circuit.

The PCM energizes the normally open 1-2 shift solenoid valve, which blocks the 1-2 signal fluid from exhausting. The 1-2 signal fluid pressure is routed to both the 1-2 and the 3-4 shift valves.

The 1-2 signal fluid pressure does not affect the 1-2 shift valve. A combination of spring force and the 2-3 signal fluid pressure keeps the 1-2 shift valve in the upshifted position.

The 1-2 signal fluid pressure moves the valve against a spring force and into the Fourth gear position. The 3-4 drive fluid is routed into the fourth band fluid circuit.

The 1-2 signal fluid pressure moves the valve against a spring force and into the Fourth gear position. The 3-4 drive fluid is routed into the fourth band fluid circuit.

The fourth band fluid is also routed to the 3-4 accumulator piston. Fourth band fluid pressure moves the piston against a combination of spring force and 3-4 accumulator feed fluid pressure. This action absorbs initial fourth band fluid pressure in order to cushion the intermediate and Fourth band apply. The movement of the 3-4 accumulator piston forces some fluid out of the accumulator.

The 3-4 accumulator feed fluid which is forced from the 3-4 accumulator unseats the #7 checkball and the fluid is routed back to the 3-4 accumulator valve. This pressure forces the 1-2/3-4 accumulator valve against a combination of spring force and torque signal fluid pressure in order to regulate the exhaust of excess accumulator fluid. This regulation provides additional control for the intermediate and fourth band apply.

When conditions are appropriate, the PCM energized the TCC control solenoid valve in order to initiate the TCC apply. The solenoid valve is pulse width modulated (PWM) in order to provide a smooth TCC apply (Refer to the electrical controls section for a detailed description of the TCC control solenoid valve operation). When energized, the solenoid valve modulates the filtered 2-3 drive fluid into the TCC signal fluid circuit.

TCC Signal fluid pressure modulates the valve against a combination of spring force and TCC regulated apply fluid pressure. This action directs line pressure into the TCC regulated apply fluid circuit in relation to vehicle operating conditions.

Modulated TCC signal fluid pressure moves the valve against a spring force in relation to vehicle operating conditions. This action regulates TCC regulated apply fluid into the apply fluid circuit. At the same time, the release fluid circuit is opened to an orificed exhaust. In this position the valve directs TCC feed limit fluid in order to feed the cooler fluid circuit.

During the downshift, except for a coastdown, the PCM senses the increase in the throttle position or the engine load. When this occurs the PCM increases the PCS duty cycle. The increase in duty cycle increases the output fluid pressure from the PCS, thereby increasing the torque signal fluid pressure at the torque signal regulator valve.

Increased torque signal fluid pressure acting on the boost valve increases line pressure at the pressure regulator valve.

The PCM de-energizes the normally open solenoid valve and the 1-2 signal fluid exhausts.

The 1-2 signal fluid pressure exhausts from the 3-4 shift valve and a spring force moves the valve into the Third gear position. This opens the Fourth band fluid circuit to an orificed exhaust in order to help control the band release.

Fourth band fluid exhausts from the servo and a spring force moves the servo to the release position, thereby releasing the band.

The fourth band fluid exhausts from the accumulator. A combination of spring force and 3-4 accumulator feed fluid pressure moves the accumulator piston to the Third gear position.

1-2/3-4 Accumulator Valve

The accumulator valve regulates line pressure into the 1-2/3-4 accumulator fluid circuit in order to fill the 3-4 accumulator. Torque signal fluid pressure controls this regulation. Increased torque signal fluid pressure regulates accumulator fluid to a higher pressure.

Drive Range, Manual Third (from Overdrive Range) (W/o Electronic Range Select Mode)

A manual 4-3 downshift is accomplished by moving the gear selector lever to the Manual Third (3) position. In Manual Third the transmission is hydraulically prevented from upshifting into Fourth gear under any conditions. Also, the coast clutch is applied in all manual ranges in order to provide engine compressing braking whenever appropriated. The following information explains the additional changes during a Manual 4-3 downshift as compared to a forced 4-3 downshift. Refer to Overdrive Range, 4-3 Downshift - Torque Converter Clutch (TCC) Not Applied (W/o Electronic Range Select Mode) for a complete description of a 4-3 downshift.

The manual valve moves into the Manual Third (3) position and line pressure enters the D321 fluid circuit. Also the manual valve blocks line pressure from the PRND4 fluid circuit and the PRND4 fluid exhausts past the manual valve.

D321 fluid pressure assists a spring force in order to keep the valve in the Third gear position under any conditions. This opens the Forth band fluid circuit to an orificed exhaust and the Intermediate and Fourth band releases, thereby preventing Fourth gear.

Manual Third - Second and First Gears

The transmission operates the same in Manual Third as in Overdrive range with the exception that Fourth gear is prevented. The transmission will upshift and downshift between First, Second, and Third gears as in Overdrive range. However, engine compression braking is not available in Manual Third - First and Second gears, and the vehicle will coast when you release the throttle.

Scheme 200

Manual Third Gear (With Electronic Range Select Mode)

A manual 4-3 downshift is accomplished by moving the gear selector lever to the Manual Third (3) position. In Manual Third the transmission is hydraulically prevented from upshifting into Fourth gear under any conditions. Also, the coast clutch is applied in all manual ranges in order to provide engine compressing braking whenever appropriated. The following information explains the additional changes during a Manual 4-3 downshift as compared to a forced 4-3 downshift. Refer to Overdrive Range, 4-3 Downshift - Torque Converter Clutch (TCC) Not Applied (W/o Electronic Range Select Mode) for a complete description of a 4-3 downshift.

The manual valve moves into the Manual Third (3) position and line pressure enters the D321 fluid circuit. Also the manual valve blocks line pressure from the PRND4 fluid circuit and the PRND4 fluid exhausts past the manual valve.

D321 fluid pressure assists a spring force in order to keep the valve in the Third gear position under any conditions. This opens the Forth band fluid circuit to an orificed exhaust and the Intermediate and Fourth band releases, thereby preventing Fourth gear.

The transmission operates the same in Manual Third as in Overdrive range with the exception that Fourth gear is prevented. The transmission will upshift and downshift between First, Second, and Third gears as in Overdrive range. However, engine compression braking is not available in Manual Third - First and Second gears, and the vehicle will coast when you release the throttle.

Scheme 201

Drive Range, Manual Second (from Drive, Manual Third) (W/o Electronic Range Select Mode)

A manual 3-2 downshift is initiated by moving the gear selector lever to the Manual Second (2) position. However, the transmission will not downshift into Second gear until vehicle speed is below approximately 99 km/h (62 mph). At higher vehicle speeds the PCM will keep the 2-3 shift solenoid energized (On) and the transmission will operate in Manual Second - Third Gear as a safety precaution. In Manual Second the transmission is hydraulically prevented from upshifting into Fourth gear under any conditions. Also, the coast clutch remains applied as in Manual Third, and the clutch provides engine compression braking in the Third and the Second gears. The transmission upshifts and downshifts between First and Second gears as in Overdrive gear.

Line pressure is routed into the D21 fluid circuit when the selector lever is moved into the Manual Second (2) position. Line pressure continues to feed the D321 fluid circuit as in Manual Third.

The PCM de-energized the 2-3 shift solenoid valve when the vehicle operating conditions are appropriate for a 3-2 downshift. With the solenoid valve Off, a 2-3 signal fluid exhausts through the 2-3 shift solenoid valve.

A spring force moves the 2-3 shift valve into the Second gear position when the 2-3 signal fluid exhausts. The D21 fluid continues through the valve and the fluid is also routed into the intermediate band feed fluid circuit. The 3-4 drive fluid, which feeds the direct clutch, exhausts past the 2-3 shift valve.

The direct clutch fluid exhausts and the direct clutch releases.

#6 Checkball (Direct Clutch Release)

Exhausting direct clutch fluid seats the #6 checkball. This fluid is forced through the #25 orifice in order to help to control the direct clutch release.

Direct clutch feed fluid exhausts from the 2-3 accumulator, unseats the #5 checkball, and exhausts past the 2-3 shift valve. The 2-3 accumulator feed fluid fills the 2-3 accumulator as the direct clutch feed fluid exhausts.

The 1-2 shift solenoid valve is Off when the PCM commands the Second gear. A spring force holds the 1-2 shift valve in the upshifted position. Intermediate band feed fluid is routed through the valve and into the intermediate band fluid circuit.

#3 Checkball (Intermediate Band Apply)

Intermediate band fluid pressure seats the #3 checkball and is forced through the #8 orifice. This orifice helps to control the intermediate band apply.

Intermediate band fluid pressure is routed to the inner area of the intermediate and Fourth servo piston. This fluid pressure moves the servo piston and apply pin in order to apply the intermediate and Fourth band. The band provides engine compression braking in Manual Second - Second Gear.

Pressure Control Solenoid Valve

The PCM increases the PCS duty cycle in order to increase the operating range of torque signal fluid pressure in Manual Second. This provides increased line pressure for the additional torque requirements during engine compression braking and increased engine load in Manual Second.

Manual Second Gear (With Electronic Range Select Mode)

A manual 3-2 downshift is initiated by moving the gear selector lever to the Manual Second (2) position. However, the transmission will not downshift into Second gear until vehicle speed is below approximately 99 km/h (62 mph). At higher vehicle speeds the PCM will keep the 2-3 shift solenoid energized (On) and the transmission will operate in Manual Second - Third Gear as a safety precaution. In Manual Second the transmission is hydraulically prevented from upshifting into Fourth gear under any conditions. Also, the coast clutch remains applied as in Manual Third, and the clutch provides engine compression braking in the Third and the Second gears. The transmission upshifts and downshifts between First and Second gears as in Overdrive gear.

Line pressure is routed into the D21 fluid circuit when the selector lever is moved into the Manual Second (2) position. Line pressure continues to feed the D321 fluid circuit as in Manual Third.

The PCM de-energized the 2-3 shift solenoid valve when the vehicle operating conditions are appropriate for a 3-2 downshift. With the solenoid valve Off, a 2-3 signal fluid exhausts through the 2-3 shift solenoid valve.

A spring force moves the 2-3 shift valve into the Second gear position when the 2-3 signal fluid exhausts. The D21 fluid continues through the valve and the fluid is also routed into the intermediate band feed fluid circuit. The 3-4 drive fluid, which feeds the direct clutch, exhausts past the 2-3 shift valve.

The direct clutch fluid exhausts and the direct clutch releases.

Exhausting direct clutch fluid seats the #6 checkball. This fluid is forced through the #25 orifice in order to help to control the direct clutch release.

Direct clutch feed fluid exhausts from the 2-3 accumulator, unseats the #5 checkball, and exhausts past the 2-3 shift valve. The 2-3 accumulator feed fluid fills the 2-3 accumulator as the direct clutch feed fluid exhausts.

The 1-2 shift solenoid valve is Off when the PCM commands the Second gear. A spring force holds the 1-2 shift valve in the upshifted position. Intermediate band feed fluid is routed through the valve and into the intermediate band fluid circuit.

Intermediate band fluid pressure seats the #3 checkball and is forced through the #8 orifice. This orifice helps to control the intermediate band apply.

Intermediate band fluid pressure is routed to the inner area of the intermediate and Fourth servo piston. This fluid pressure moves the servo piston and apply pin in order to apply the intermediate and Fourth band. The band provides engine compression braking in Manual Second - Second Gear.

The PCM increases the PCS duty cycle in order to increase the operating range of torque signal fluid pressure in Manual Second. This provides increased line pressure for the additional torque requirements during engine compression braking and increased engine load in Manual Second.

Drive Range, Manual First (from Drive, Manual Second) (W/o Electronic Range Select Mode)

A manual 2-1 downshift is initiated by moving the gear selector lever to the Manual First (1) position. However, the transmission will not downshift into First gear until the vehicle speed is below approximately 60 km/h (37 mph). At higher vehicle speeds the PCM will keep the 1-2 shift solenoid valve de-energized (Off) and the transmission will operate in Manual First - Second Gear. In Manual First the transmission is electronically prevented from upshifting into Third or Fourth gears under any conditions. Also, the coast clutch remains applied, as in Manual Third and Manual Second, and the clutch provides engine compression braking in First and Second gears.

Line pressure is routed into the Low fluid circuit when the selector lever is moved into the Manual First (1) position. Line pressure continues to feed the Drive, the D321, and the D21 fluid circuits as in Manual Second.

#1 Checkball (Low/PRN)

Low fluid pressure seats the #1 checkball against the PRN fluid circuit and this pressure fills the Low/PRN fluid circuit. Low/PRN fluid is routed to the 1-2 shift valve.

The PCM energizes the 1-2 shift solenoid valve when vehicle speed is below approximately 48-56 km/h (30-35 mph). The 1-2 signal fluid is blocked from exhausting through the solenoid valve.

The 1-2 signal fluid pressure shifts the valve into the downshifted position against a spring force, and the following changes occur

1. The 2-3 drive fluid circuit is open to an exhaust past the valve
2. The intermediate band fluid is exhausted past the valve
3. The Lo/PRN fluid is routed into the low band fluid circuit

The Second clutch fluid exhausts from the clutch piston and through the 2-3 drive fluid circuit. This releases the Second clutch, and the transmission operates in First gear.

Second clutch feed fluid exhausts from the 1-2 accumulator, and the fluid exhausts past the #2 checkball and through the 2-3 drive fluid circuit. The 1-2 accumulator feed fluid fills the 1-2 accumulator as the second clutch fluid exhausts.

The accumulator valve regulates the line pressure into the 1-2/3-4 accumulator fluid circuit in order to fill the 1-2 accumulator. Torque signal fluid pressure controls this regulation. Accumulator fluid pressure is regulated to a higher pressure with greater torque signal fluid pressure.

Filtered 2-3 drive fluid exhausts from the solenoid and through the 2-3 drive fluid circuit.

Intermediate band fluid exhausts from the servo piston. A spring force moves the piston and the apply pin, and the intermediate and fourth band releases. However, the intermediate and fourth band remains applied in Manual First - Second Gear in order to achieve engine compression braking.

Low band fluid pressure is routed to the inner area of the Low and Reverse servo in order to apply the Low and Reverse band. The Low and Reverse band provides engine compression braking when the throttle is released in Manual First - First Gear.

Scheme 202

Manual First Gear (With Electronic Range Select Mode)

A manual 2-1 downshift is initiated by moving the gear selector lever to the Manual First (1) position. However, the transmission will not downshift into First gear until the vehicle speed is below approximately 60 km/h (37 mph). At higher vehicle speeds the PCM will keep the 1-2 shift solenoid valve de-energized (Off) and the transmission will operate in Manual First - Second Gear. In Manual First the transmission is electronically prevented from upshifting into Third or Fourth gears under any conditions. Also, the coast clutch remains applied, as in Manual Third and Manual Second, and the clutch provides engine compression braking in First and Second gears.

Line pressure is routed into the Low fluid circuit when the selector lever is moved into the Manual First (1) position. Line pressure continues to feed the Drive, the D321, and the D21 fluid circuits as in Manual Second.

Low fluid pressure seats the #1 checkball against the PRN fluid circuit and this pressure fills the Low/PRN fluid circuit. Low/PRN fluid is routed to the 1-2 shift valve.

The PCM energizes the 1-2 shift solenoid valve when vehicle speed is below approximately 48-56 km/h (30-35 mph). The 1-2 signal fluid is blocked from exhausting through the solenoid valve.

The 1-2 signal fluid pressure shifts the valve into the downshifted position against a spring force, and the following changes occur

1. The 2-3 drive fluid circuit is open to an exhaust past the valve
2. The intermediate band fluid is exhausted past the valve
3. The Lo/PRN fluid is routed into the low band fluid circuit

The Second clutch fluid exhausts from the clutch piston and through the 2-3 drive fluid circuit. This releases the Second clutch, and the transmission operates in First gear.

Second clutch feed fluid exhausts from the 1-2 accumulator, and the fluid exhausts past the #2 checkball and through the 2-3 drive fluid circuit. The 1-2 accumulator feed fluid fills the 1-2 accumulator as the second clutch fluid exhausts.

The accumulator valve regulates the line pressure into the 1-2/3-4 accumulator fluid circuit in order to fill the 1-2 accumulator. Torque signal fluid pressure controls this regulation. Accumulator fluid pressure is regulated to a higher pressure with greater torque signal fluid pressure.

Filtered 2-3 drive fluid exhausts from the solenoid and through the 2-3 drive fluid circuit.

Intermediate band fluid exhausts from the servo piston. A spring force moves the piston and the apply pin, and the intermediate and fourth band releases. However, the intermediate and fourth band remains applied in Manual First - Second Gear in order to achieve engine compression braking.

Low band fluid pressure is routed to the inner area of the Low and Reverse servo in order to apply the Low and Reverse band. The Low and Reverse band provides engine compression braking when the throttle is released in Manual First - First Gear. The low band fluid is routed to the 3-4 shift valve. The pressure moves the 3-4 shift valve against the 1-2 signal fluid.

Scheme 203

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