Nissan Sentra manuals

Nissan Sentra Service Manual: Structure and operation

TRANSAXLE

TRANSAXLE : Cross-Sectional View


  1. Converter housing
  2. Oil pump
  3. Counter drive gear
  4. Control valve
  5. Oil pan
  6. Primary pulley
  7. Steel belt
  8. Secondary pulley
  9. Planetary gear (auxiliary gearbox)
  10. Side cover
  11. Transaxle case
  12. Differential case
  13. Final gear
  14. Reduction gear
  15. Counter driven gear
  16. Drive sprocket
  17. Oil pump chain
  18. Torque converter
  19. Driven sprocket

TRANSAXLE : Operation Status

TRANSAXLE : Transaxle Mechanism


TRANSAXLE : Transaxle Mechanism

BELT & PULLEY

Mechanism

It is composed of a pair of pulleys (the groove width is changed freely in the axial direction) and the steel belt (the steel plates are placed continuously and the belt is guided with the multilayer steel rings on both sides).

The groove width changes according to wrapping radius of steel belt and pulley from low status to overdrive status continuously with non-step. It is controlled with the oil pressures of primary pulley and secondary pulley.

Steel belt

It is composed of multiple steel plates and two steel rings stacked to a several number. The feature of this steel belt transmits power with compression of the steel plate in contrast with transmission of power in pulling with a rubber belt. Friction force is required with the pulley slope to transmit power from the steel plate. The force is generated with the following mechanism: Oil pressure applies to the secondary pulley to nip the plate. ⇒The plate is pushed and extended outward. ⇒The steel ring shows withstands.

⇒Pulling force is generated on the steel ring. ⇒The plate of the primary pulley is nipped between the pulley. ⇒Friction force is generated between the steel belt and the pulley.

Therefore, responsibilities are divided by the steel plate that transmits the power with compression and the steel ring that maintains necessary friction force. In this way, the tension of the steel ring is distributed on the entire surface and stress variation is limited, resulting in good durability.

Pulley


Pulley

The primary pulley (input shaft side) and the secondary pulley (output shaft side) have the shaft with slope (fixed cone surface), movable sheave (movable cone surface that can move in the axial direction) and oil pressure chamber at the back of the movable sheave.

Pulley gear shifting operation


Pulley gear shifting operation

The movable sheave slides on the shaft to change the groove width of the pulley. Input signals of engine load (accelerator pedal opening), engine revolution and gear ratio (vehicle speed) change the operation pressures of the primary pulley and the secondary pulley, and controls the pulley groove width. Along with change of the pulley groove width, the belt contact radius is changed. This allows continuous and stepless gear shifting from low to overdrive. “The contact radius ratio of each pulley in contact with the belt x auxiliary gearbox gear ratio” is the gear ratio.

AUXILIARY GEARBOX MECHANISM


AUXILIARY GEARBOX MECHANISM

1st, 2nd and reverse gears are changed with the planetary gear mechanism.

TRANSAXLE : Oil Pressure System

Oil pressure required for operation of the transaxle transmission mechanism is generated by oil pump, oil pressure control valve, solenoid valve, etc.

TRANSAXLE : Component Description


TRANSAXLE : Component Description

Part name

Function

Torque converter It is composed of the cover converter, turbine assembly, stator, pump impeller assembly, etc. It increases the engine torque and transmits the power to the transaxle.
Oil pump Through the oil pump drive chain, it uses the vane oil pump driven by the engine. It generates necessary oil pressure to circulate fluid and to operate the clutch and brake.
Counter gear set The power from the torque converter is transmitted to the primary pulley through the counter drive gear and the counter driven gear.
Belt & pulley (Continuously variable transmission) It is composed of the primary pulley, secondary pulley, steel belt, etc. and the mechanism performs shifting, changes the gear ratio and transmits the power with oil pressure from the control valve.
Auxiliary gearbox (stepped transmission) It is composed of the planetary gear, multi-disc clutch, multi-disc brake, etc. and the mechanism performs shifting (1-2 gear shifting and reverse) with oil pressure from the control valve.
Reduction gear set Conveys power from the transmission mechanism to the reduction gear and the final gear.
Parking mechanism When the shift lever is changed to P position, the mechanism fixes the parking gear (integrated with the reduction gear) and the fixes the output shaft
Control valve Controls oil pressure from the oil pump to the pressure suitable for the line pressure control system, shift control system, lock-up control system and lubrication system.
Pressure regulator valve Adjusts the discharge pressure from the oil pump to the optimum pressure (line pressure) corresponding to the driving condition.
Torque converter regulator valve Adjusts the feed pressure to the torque converter to the optimum pressure corresponding to the driving condition.
Pilot valve Adjusts line pressure and produces a constant pressure (pilot pressure) necessary for activating each solenoid valve.
Manual valve Distributes the clutch and brake operation pressures (pilot pressure) corresponding to each shift position.
High clutch/reverse brake switching valve Switches the circuit for the high clutch and the reverse brake.
Torque converter clutch control valve It is operated with the torque converter clutch solenoid valve and it adjusts the tightening pressure and non-tightening pressure of the torque converter clutch piston of the torque converter.
Primary pressure control valve It is operated with the primary pressure solenoid valve and adjusts the feed pressure to the primary pulley.
Primary pressure solenoid valve TM-79, "CVT CONTROL SYSTEM : Primary Pressure Solenoid Valve"
Low brake solenoid valve TM-79, "CVT CONTROL SYSTEM : Low Brake Solenoid Valve"
High clutch & reverse brake solenoid valve TM-80, "CVT CONTROL SYSTEM : High Clutch & Reverse Brake Solenoid Valve"
Torque converter clutch solenoid valve TM-80, "CVT CONTROL SYSTEM : Torque Converter Clutch Solenoid Valve"
Line pressure solenoid valve TM-81, "CVT CONTROL SYSTEM : Line Pressure Solenoid Valve"

FLUID COOLER & FLUID WARMER SYSTEM

FLUID COOLER & FLUID WARMER SYSTEM :System Description

CVT FLUID COOLER SCHEMATIC

COMPONENT DESCRIPTION


COMPONENT DESCRIPTION

CVT Oil Warmer

Heater Thermostat


SHIFT LOCK SYSTEM


SHIFT LOCK SYSTEM

SHIFT LOCK SYSTEM : System Description

SHIFT LOCK OPERATION AT P POSITION

When brake pedal is not depressed (no selector operation allowed) When the brake pedal is not depressed with the ignition switch ON, the shift lock solenoid energized) and the solenoid rod  is OFF (not
energized) and the solenoid rod with spring. is extended
with spring.

The connecting lock lever shown in the is located at the position
shown in the figure when the solenoid rod is extended. It prevents the movement of the detent rod  . The selector lever cannot be shifted from the “P”
 . The selector lever cannot be shifted from the “P” position for this reason.

When brake pedal is depressed (selector lever operation allowed)


When brake pedal is depressed (selector lever operation allowed) The shift lock solenoid when the brake is turned ON (energized)
when the brake pedal is depressed with the ignition switch ON. The solenoid rod is compressed with the electromagnetic force. The connecting lock lever rotates when the solenoid rod is compressed. Therefore, the
rotates when the solenoid rod is compressed. Therefore, the detent rod can be moved shifted to . The selector lever can be
shifted to other positions for this reason.

P POSITION HOLD MECHANISM (IGNITION SWITCH LOCK)


P POSITION HOLD MECHANISM (IGNITION SWITCH LOCK)

The shift lock solenoid in any position other than ON. The shift mechanism is locked and “P” is not energized when the ignition switch is
in any position other than ON. The shift mechanism is locked and “P” position is held. The operation cannot be performed from “P” position if the brake pedal is depressed with the ignition switch ON when the operation system of shift lock solenoid is malfunctioning. However, the lock lever  is forcibly rotated and the shift lock is released when
 is forcibly rotated and the shift lock is released when the shift lock release button above. The selector  is pressed from
above. The selector operation from “P” position can be performed.

CAUTION: : Detent rod


CAUTION:

Use the shift lock release button only when the selector lever cannot be operated even if the brake pedal is depressed with the ignition switch ON.

KEY LOCK SYSTEM

KEY LOCK SYSTEM : System Description

KEY LOCK MECHANISM

The key is not set to LOCK when the selector lever is not selected to P position. This prevents the key from being removed from the key cylinder.

Key lock status

The slider when the selector lever is in any position other than “P” position. in the key cylinder when the selector lever is in any position other than “P” position. is moved to the left side of the figure
when the selector lever is in any position other than “P” position.

The rotator rotates together with the key cannot be rotated  that
rotates together with the key cannot be rotated for this reason. The key cannot be removed from the key cylinder because it cannot be turned to LOCK .


Key unlock status


Key unlock status

The slider figure when the selector lever is in “P” position and the finger is in the key cylinder figure when the selector lever is in “P” position and the finger is is moved to the right side of the
figure when the selector lever is in “P” position and the finger is removed from the selector button. The rotator rotated for can be
rotated for this reason. The key because it can be turned to LOCK  . can be removed from the key cylinder
because it can be turned to LOCK .


System


System description
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Other materials:

Av branch line circuit
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Three-way catalyst
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Doors
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