Automatic Transmission: Overview Infiniti M37 IV

A/T CONTROL SYSTEM: Component Description

A/T SHIFT LOCK SYSTEM: Component Description

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DESCRIPTION

With the use of 4 sets of planetary gears, A/T enables 7-speed transmission for forward and 1-speed transmission for backward, depending on the combination of 3 sets of multiple-disc clutches, 4 sets of multiple-disc brakes and 2 sets of one-way clutches.

Scheme 5

Scheme 6

Since the low brake is released, torque from the input shaft drive is not transmitted to the output shaft.

Scheme 7

1. The same as for the "N" position, since the low brake is released, so torque from the input shaft drive is not P transmitted to the output shaft.
2. The parking pawl linked with the selector lever meshes with the parking gear and fastens the output shaft mechanically.

Scheme 8

1. The 1st one-way clutch regulates counterclockwise rotation of the under drive carrier.
2. The 2nd one-way clutch regulates counterclockwise rotation of the rear sun gear.
3. The mid sun gear is fixed by the low brake.
4. Each planetary gear enters the state described below.

FRONT PLANETARY GEAR

UNDER DRIVE PLANETARY GEAR

REAR PLANETARY GEAR

MID PLANETARY GEAR

Scheme 9

1. The 1st one-way clutch and the front brake regulate counterclockwise rotation of the under drive carrier. NOTE: The front brake operates only while coasting.
2. The 2nd one-way clutch and the high and low reverse clutch regulate counterclockwise rotation of the rear sun gear. NOTE: The high and low reverse clutch operates only while coasting.
3. The mid sun gear is fixed by the low brake.

1. Each planetary gear enters the state described below.

FRONT PLANETARY GEAR

UNDER DRIVE PLANETARY GEAR

REAR PLANETARY GEAR

MID PLANETARY GEAR

Scheme 10

1. The front sun gear and the under drive sun gear are fixed by the 2346 brake.
2. The 2nd one-way clutch regulates counterclockwise rotation of the rear sun gear.
3. The mid sun gear is fixed by the low brake.
4. Each planetary gear enters the state described below.

FRONT PLANETARY GEAR

UNDER DRIVE PLANETARY GEAR

REAR PLANETARY GEAR

MID PLANETARY GEAR

Scheme 11

1. The front sun gear and the under drive sun gear are fixed by the 2346 brake.
2. The 2nd one-way clutch and the high and low reverse clutch regulate counterclockwise rotation of the rear sun gear. NOTE: The high and low reverse clutch operates only while coasting.
3. The mid sun gear is fixed by the low brake.
4. Each planetary gear enters the state described below.

FRONT PLANETARY GEAR

UNDER DRIVE PLANETARY GEAR

REAR PLANETARY GEAR

MID PLANETARY GEAR

Scheme 12

1. The front sun gear and the under drive sun gear are fixed by the 2346 brake.
2. The direct clutch gets engaged and connects the rear sun gear with the rear carrier.
3. The mid sun gear is fixed by the low brake.
4. Each planetary gear enters the state described below.

FRONT PLANETARY GEAR

UNDER DRIVE PLANETARY GEAR

REAR PLANETARY GEAR

MID PLANETARY GEAR

Scheme 13

1. The front sun gear and the under drive sun gear are fixed by the 2346 brake.
2. The direct clutch gets engaged and connects the rear sun gear with the rear carrier.
3. The high and low reverse clutch gets engaged and connects the rear sun gear with the mid sun gear.
4. Each planetary gear enters the state described below.

FRONT PLANETARY GEAR

UNDER DRIVE PLANETARY GEAR

REAR PLANETARY GEAR

MID PLANETARY GEAR

Scheme 14

1. The input clutch gets engaged and connects the mid internal gear with the rear carrier.
2. The direct clutch gets engaged and connects the rear sun gear with the rear carrier.
3. The high and low reverse clutch gets engaged and connects the rear sun gear with the mid sun gear.
4. Each planetary gear enters the state described below.

REAR PLANETARY GEAR

MID PLANETARY GEAR

Scheme 15

1. The front sun gear and the under drive sun gear are fixed by the 2346 brake.
2. The input clutch gets engaged and connects the mid internal gear with the rear carrier.
3. The high and low reverse clutch gets engaged and connects the rear sun gear with the mid sun gear.
4. Each planetary gear enters the state described below.

FRONT PLANETARY GEAR

REAR PLANETARY GEAR

MID PLANETARY GEAR

Scheme 16

1. The under drive carrier is fixed by the front brake.
2. The input clutch gets engaged and connects the mid internal gear with the rear carrier.
3. The high and low reverse clutch gets engaged and connects the rear sun gear with the mid sun gear.
4. Each planetary gear enters state described below.

FRONT PLANETARY GEAR

UNDER DRIVE PLANETARY GEAR

REAR PLANETARY GEAR

MID PLANETARY GEAR

Scheme 17

1. The 1st one-way clutch and the front brake regulate counterclockwise rotation of the under drive carrier. NOTE: The front brake operates at the fixed speed or less.
2. The rear carrier and the mid internal gear are fixed by the reverse brake.
3. The mid sun gear rotates at the same speed as the rear sun gear by operation of the 2nd one-way clutch and the high and low reverse clutch.

Note. The high and low reverse clutch operates at the fixed speed or less.

1. Each planetary gear enters the state described below. FRONT PLANETARY GEAR Name Front sun gear Front carrier Front internal gear Condition - Output Input Direction of rotation Counterclockwise revolution Clockwise revolution Clockwise revolution Number of revolutions Deceleration from front internal gear Deceleration from front internal gear Same number of revolution as the input shaft UNDER DRIVE PLANETARY GEAR Name Under drive sun gear Under drive carrier Under drive internal gear Condition - Fixed Input/Output Direction of rotation Counterclockwise revolution - Clockwise revolution Number of revolutions Acceleration from under drive internal gear - Same number of revolution as the front carrier REAR PLANETARY GEAR Name Rear sun gear Rear carrier Rear internal gear Condition Output Fixed Input Direction of rotation Counterclockwise revolution - Clockwise revolution Number of revolutions Acceleration from rear internal gear - Same number of revolution as the under drive internal gear MID PLANETARY GEAR Name Mid sun gear Mid carrier Mid internal gear Condition Input Output Fixed Direction of rotation Counterclockwise revolution Counterclockwise revolution - Number of revolutions Same number of revolution as the rear sun gear Deceleration from mid sun gear

Component Description

Scheme 18

SYSTEM DESCRIPTION

1. The A/T senses vehicle operating conditions through various sensors or signals. It always controls the optimum shift position and reduces shifting and lock-up shocks.
2. Receive input signals transmitted from various switches and sensors.
3. Determine required line pressure, shifting point, lock-up operation, etc.
4. Transmit required output signals to the respective solenoids.

LINE PRESSURE CONTROL: System Description

1. When an engine and A/T integrated control signal (engine torque) equivalent to the engine drive force is transmitted from the ECM to the TCM, the TCM controls the line pressure solenoid valve. This line pressure solenoid controls the pressure regulator valve as the signal pressure and adjusts the pressure of the operating oil discharged from the oil pump to the line pressure most appropriate to the driving state.
2. The TCM has stored in memory a number of patterns for the optimum line pressure characteristic for the driving state.
3. In order to obtain the most appropriate line pressure characteristic to meet the current driving state, the TCM controls the line pressure solenoid current value and thus controls the line pressure.

SHIFT CHANGE CONTROL: System Description

INPUT/OUTPUT SIGNAL CHART

The clutch pressure control solenoid is controlled by the signals from the switches and sensors. Thus, the clutch pressure is adjusted to be appropriate to the engine load state and vehicle driving state. It becomes possible to finely control the clutch hydraulic pressure with high precision and a smoother shift change characteristic is attained.

Scheme 19

The clutch is controlled with the optimum timing and oil pressure by the engine speed, engine torque information, etc.

Scheme 20

*1: Full phase real-time feedback control monitors movement of gear ratio at gear change, and controls oil pressure in real-time to achieve the best gear ratio.

A/T SHIFT LOCK SYSTEM: System Description

1. Shift lock prevents an unintentional start of the vehicle that may be caused by an incorrect operation while selector lever is in the "P" position.
2. Selector lever can be shifted from the "P" position to another position when the following conditions are satisfied.

1. Ignition switch ON
2. Stop lamp switch is ON (brake pedal is depressed)
3. Selector lever knob button is pressed

Scheme 21

SHIFT LOCK OPERATION

When brake pedal is not depressed and selector lever is in "P" position. (Unable to shift selector lever.) Without brake pedal depressed and with ignition switch ON, electromagnet (A) of slider (B) is not magnetized because of non electrical current. When selector lever knob button is pressed in this situation, detent pin (C) lowers. According to the movement of detent pin, plate (D) also lowers while pressing slider into shift lock unit. However, stopper (E) pressed by spring comes underneath plate. Plate cannot lower further when it contacts stopper, and detent pin cannot lower to the point that releases selector lever. Thus selector lever stays in the "P" position and selector lever is unable to shift. When brake pedal is depressed and selector lever is in "P" position. (Able to shift selector lever.)

Scheme 22

With brake pedal depressed and with ignition switch ON, electromagnet (A) of slider (B) becomes magnetized because of live electricity. stopper (C) has an iron plate (D) to unify stopper with slider when electromagnet becomes magnetized. When selector lever knob button is pressed in this situation, detent pin (E) lowers. According to the movement of detent pin, plate (F) also lowers while pressing slider into shift lock unit. Because stopper is unified with slider, the slider unit moves into shift lock unit. Detent pin lowers to the point that releases selector lever from the "P" position and selector lever becomes able to shift.

Scheme 23

Diagnosis Description

The A/T system has two self-diagnostic systems. The first is the emission-related on board diagnostic system (OBD-II) performed by the TCM in combination with the ECM. A malfunction is indicated by the MIL (malfunction indicator lamp) and is stored as a DTC in the

ECM memory and in the TCM memory. The second is the TCM original self-diagnosis indicated by the TCM. A malfunction history is stored in the TCM memory. The detected items are overlapped with OBD-II self-diagnostic items. For details, refer to " DTC INDEX ".

There are many operating conditions that may cause a malfunction of the transmission parts. By understanding those conditions properly, a quick and exact diagnosis can be achieved.

In general, customers have their own criteria for a problem. Therefore, it is important to understand the symptom and status well enough by asking the customer about the concerns carefully. In order to systemize all the information for the diagnosis, prepare the question sheet referring to the question points.

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Decel G sensor calibration must be performed when replacing A/T assembly.

Decel G sensor calibration must be performed when replacing A/T assembly.

Decel G sensor calibration must be performed when the following operation is performed.

1. Removal and installation or replacement of yaw rate/side/decel G sensor
2. Replacement of A/T assembly
3. Replacement of control valve & TCM
4. Replacement of ABS actuator and electric unit (control unit)

The amount of data transmitted from each control unit is read.

CAN (Controller Area Network) is a serial communication line for real-time application. It is an on-vehicle multiplex communication line with high data communication speed and excellent malfunction detection ability. Many electronic control units are equipped onto a vehicle, and each control unit shares information and links with other control units during operation (not independently). In CAN communication, control units are connected with 2 communication lines (CAN-H line, CAN-L line) allowing a high rate of information transmission with less wiring. Each control unit transmits/receives data but selectively reads required data only.

TCM prohibits cranking other than at "P" or "N" position.

The engine speed signal is transmitted from the ECM to the TCM via CAN communication line.

This malfunction is detected when the A/T does not shift into 6GR position as instructed by TCM. This is not only caused by electrical malfunction (circuits open or shorted) but by mechanical malfunction such as control valve sticking, improper solenoid valve operation, etc.

1. TCM detects a high-rpm state of the under drive sun gear.
2. The number of revolutions of the under drive sun gear is calculated with the input speed sensor 1 and 2.

This malfunction is detected when the A/T does not shift into 1GR position as instructed by TCM. This is not only caused by electrical malfunction (circuits open or shorted) but by mechanical malfunction such as control valve sticking, improper solenoid valve operation, etc.

This malfunction is detected when the A/T does not shift into 2GR position as instructed by TCM. This is not only caused by electrical malfunction (circuits open or shorted) but by mechanical malfunction such as control valve sticking, improper solenoid valve operation, etc.

This malfunction is detected when the A/T does not shift into 3GR position as instructed by TCM. This is not only caused by electrical malfunction (circuits open or shorted) but by mechanical malfunction such as control valve sticking, improper solenoid valve operation, etc.

This malfunction is detected when the A/T does not shift into 4GR position as instructed by TCM. This is not only caused by electrical malfunction (circuits open or shorted) but by mechanical malfunction such as control valve sticking, improper solenoid valve operation, etc.

This malfunction is detected when the A/T does not shift into 5GR position as instructed by TCM. This is not only caused by electrical malfunction (circuits open or shorted) but by mechanical malfunction such as control valve sticking, improper solenoid valve operation, etc.

This malfunction is detected when the A/T does not lock-up. This is not only caused by electrical malfunction (circuits open or shorted) but also by mechanical malfunction such as control valve sticking, improper solenoid valve operation, etc.

The TCM detects the malfunction of low brake solenoid valve. This is not only caused by electrical malfunction (circuits open or shorted) but also by mechanical malfunction such as control valve sticking, improper solenoid valve operation, etc.

The vehicle speed signal is transmitted from combination meter to TCM via CAN communication line. The signal functions as an auxiliary device to the output speed sensor when it is malfunctioning. The TCM will then use the vehicle speed signal.

Fail-safe function to detect interlock conditions.

This malfunction is detected when the A/T does not shift into 7GR position as instructed by TCM. This is not only caused by electrical malfunction (circuits open or shorted) but by mechanical malfunction such as control valve sticking, improper solenoid valve operation, etc.

TCM transmits a shift position signal and a manual mode indicator signal to the combination meter via CAN communication line. While the vehicle is running, the combination meter displays a shift position on the combination meter, according to these signals.