Transmission Description
Transmission Description
Automatic transmission JF506E
The newly developed JF506E automatic transmission has been developed for use by Jaguar. The JF506E is built in Japan by Japan Automatic Transmission Company (JATCO). The JF506E has 5-speed lock-up, which provides smooth and fast operation and employs a Transmission Control Module (TCM), three speed sensors and nine gear change solenoids to realize finer gear change control, which provides excellent response to changing driving conditions.
Automatic transmission JF506E
JF506E:
^ J = Japan automatic transmission company.
^ F = front wheel drive
^ 5 = 5 Forward gears
^ 06 = Version number
^ E = Electronic control
The transmission ID is stamped on the transmission, E.G.: PL 000 = 3.0 litre or PL 001 = 2.5 litre. This is followed by the production year and month and a 5 digit serial number - 08 XXXXX.
Range Selection
Depending on the vehicle options selected the automatic transmission range selector may have different range positions.
The standard range selector has seven positions: P, R, N, D, 4, 3 and 2.
J-Gate Range Selection
"P"
In the PARK position:
^ there is no power flow through the automatic transmission.
^ the parking pawl locks the output shaft to the case.
^ the engine may be started.
^ the ignition key may be removed.
"R"
In the REVERSE position:
^ the vehicle may be operated in a rearward direction, at a reduced gear ratio, backup lamps are illuminated.
"N"
In the NEUTRAL position:
^ there is no power flow through the automatic transmission.
^ the output shaft is not held and is free to turn.
^ the engine may be started.
"D"
Drive is the normal position for most forward driving.
The D position provides:
^ automatic shift 1-5 and 5-1.
^ apply and release of the torque converter clutch.
^ maximum fuel economy during normal operation.
^ engine braking in 5th gear.
"4"
The 4 position provides:
^ automatic shift 1-4 and 4-1.
^ apply an release of the torque converter clutch.
^ engine braking in 4th gear.
"3"
The 3 position provides:
^ third gear start and hold.
^ the torque converter clutch may apply and release.
^ improved traction on slippery roads.
^ engine braking.
"2"
The 2 position provides:
^ second gear start and hold.
^ the torque converter clutch may apply and release.
^ improved traction on slippery roads.
^ engine braking.
"S"
The Sport mode switch allows:
^ the driver to select or de-select the automatic transmission sport mode.
^ the automatic transmission to operate normally when the sport mode is selected, but under acceleration the gear shift points are extended to make full use of the engine's power reserves.
^ the driver to drive the vehicle in the "D" position with full automatic transmission shift or manually shift gears in the "2, 3 and 4" positions.
Disassembled Views
Overview
The transmission gear changes, oil pressure and lock-up operation are all electronically controlled. The TCM located in the left hand A-pillar receives electrical signals from sensors indicating vehicle speed and throttle opening. In response to these signals the TCM selects the appropriate gear and regulates other related conditions.
Actual transmission control changes are made by actuators (solenoids), that respond to input signals received from the TCM. These solenoids operate in response to electrical signals they regulate the control valve operation. The control valves cause changes in the fluid flow passages. This results in pressure changes within the transmission.
Transmission Construction
A cross-sectional view of the automatic transmission.
Torque Converter
The torque converter delivers the engine drive power to the transmission. When the lock-up clutch is released, the power delivery is depended on Automatic Transmission Fluid (ATF). When the lock-up clutch is engaged the engine power is delivered to the transmission through the lock-up clutch.
The lock-up clutch is controlled electronically and operates in 4th and 5th gears.
A symmetrical element 1-step 2-phase torque converter is used with JF506E automatic transmission. The term "1-step" refers to the single turbine and runner assembly and "2-step" refers to the turbine runner speed relative to the pump impeller speed. When the turbine runner speed is lower than the pump impeller speed, the mechanism operates as a simple torque converter. When the turbine runner speed is higher than pump impeller speed, the mechanism acts as a fluid coupling.
The torque converter transmits and multiplies torque. The torque converter is a four-element device:
^ impeller assembly
^ turbine and damper assembly
^ reactor assembly
^ clutch
The standard torque converter components operate as follows:
^ Rotation of the converter housing and impeller set the fluid in motion.
^ The turbine reacts to the fluid motion from the impeller, transferring rotation to the geartrain through the input shaft.
^ The reactor redirects fluid going back into the impeller, allowing for torque multiplication.
^ The clutch and damper assembly dampens powertrain torsional vibration and provides a direct mechanical connection for improved efficiency.
^ Power is transmitted from the torque converter to the planetary gearsets and other components through the input shaft.
Oil Pump
A trochoid oil pump is used with JF506E automatic transmission. The trochoid oil pump has the advantage of very low power loss.
The oil pump is driven by the engine. The inner rotor connects to the torque converter sleeve.
Geartrain
Power is transmitted from the torque converter to the planetary gearsets through the input shaft. Bands and clutches are used to hold and drive certain combinations of gearsets. This results in five forward ratios and one reverse ratio, which are transmitted to the output shaft and differential.
Planetary Gears
There are 3 planetary gear sets. Front, rear and reduction.
Clutches
There are 4 wet type multi disc clutches (low clutch, high clutch, reverse clutch and direct clutch).
Each clutch has two primary rotating parts (the clutch drum and the clutch hub). Power transmission is effected and controlled by these two parts.
The clutch drum and hub are connected to a clutch plate. Pressure applied to the clutch plate results in power transfer. When this pressure is released from the clutch plate, power does not transfer.
The clutch plates at the clutch drum side function as the driven plates. The clutch plates at the clutch hub side function as the drive plates. The drive plates have friction materials on the faces.
Clutch engagement occurs when oil pressure is applied to the piston in the clutch drum. The dish plate acts as a cushion to prevent sudden and violent force applied to the clutch plates, which may causes a rough clutch engagement.
The retaining plate is attached to the driven plate. The retaining plate also serves as a spacer when the clutch is disengaged. It ensures specified clutch clearance.
The piston is returned by return spring forces to ordinal position when the oil pressure is removed through the drain hole. As a result the clutch is disengaged.
The check ball is forced to seal the oil circuit by oil pressure against the oil input hole when the clutch is engaged. When the clutch is released the check ball moves back from the input hole to open the circuit and air is led into the oil chamber. This prevents residual oil pressure build-up in the clutch drum.
The clutch drum and the clutch hub are connected to the planetary gears respectively. Planetary gear rotation acts as the controlling element of the clutch.
Cancel Force Cover
Low Clutch
High Clutch
The JF506E automatic transmission is equipped with the centrifugal oil pressure cancel room in low clutch and high clutch.
The centrifugal oil pressure cancel room improves clutch release time by applying force to the low clutch and the high clutch.
This system improves operating performance of the piston compared with the check ball system.
The piston returns to the original position by centrifugal force that is kept at the pressure room located at the other side of the piston cylinder.
Therefore, the response of the clutch release operation is improved and quick gear change is obtained.
Low and Reverse Brake, 2 - 4 Brake
The low & reverse brake and the 24 brake are multi-disc type brakes. Basic brake operation is similar to the clutch. The clutch drum is mounted to an appropriate position on the transmission case. The low & reverse brake and the 24 brake act to stop the clutch hub rotation when the clutch plate is engaged.
Reduction Brake Band and Band Servo
The brake band acts in response to the servo to stop the direct clutch drum rotation.
The servo has a piston that operates in response to changes in oil pressure. The piston expands in P and N ranges, 1st, 2nd, 3rd, 4th, and reverse gears to stop the direct clutch drum rotation.
When the line pressure reaches to the band servo the servo piston works. The downward piston stroke causes the piston stem to tighten the brake band. The direct clutch drum rotation stops.
The anchor end bolt is used to maintain appropriate clearance between the brake band and the direct clutch drum when the brake band is released. This clearance can be adjusted with the adjusting nut on the anchor end bolt.
One Way Clutches
The transmission uses two one way clutches.
Low One Way Clutch
The front planetary carrier is fixed by the inner race, which runs free during 1st gear operation.
Reduction One Way Clutch
The reduction sun gear is fixed by the inner race which runs free during 1st, 2nd, 3rd and 4th gear operations.
Roller-Type One-Way Clutch
Normally, rollers are energized to the narrower section via a spring. Therefore, in the direction where the rollers are engaged between the cam and inner race they are united to transmit torque. In the reverse direction, because the rollers move in the direction where the clearance is larger, clearances occur between races and the inner and outer races can rotate to each other.
Sprag-Type One-Way Clutch
Note the difference between sprag diameters "A" and "B" If the inner race tries to turn toward the left, radius "B" (longer than gap "C") firmly locks the sprag to prevent the sprag from moving to the left.
Solenoids
There are 9 solenoids, which can be classified as two types by the way in which they operate. Three of them are duty solenoids, the other six are on/off types. The solenoids are actuated by the TOM output signals.
On/Off Solenoids
Shift solenoids A, B, C, low clutch solenoid, reduction timing solenoid and the 2/4 brake timing solenoid
The on/off solenoids close the pressure circuit in response to current flow.
Each solenoid has an internal coil. Current passes through coil and actuates the needle valve. The needle valve then opens and closes the fluid pressure circuits.
Duty Solenoids
Line pressure solenoid, lock-up solenoid and the 2/4 brake duty solenoid.
The duty solenoids repeatedly turn on/off in 50Hz cycles, this opens and closes the fluid pressure circuits.
Sensors
Sensor Schematic
Transmission Fluid Temperature (TFT) Sensor
The TFT sensor is installed in the transmission case, it constantly monitors the fluid temperature resistance varies with fluid temperature.
Automatic transmission internal operational resistance varies with automatic transmission fluid temperature change. The TOM detects the automatic transmission fluid temperature according to the voltage produced by the TFT sensor.
Speed Sensors
There are 3 sensors installed in the transmission casing. They are all of the inductive type.
Turbine Shaft Speed Sensor
The Turbine Shaft Speed Sensor (TSS) detects the reverse clutch drum revolution speed. The reverse clutch drum is connected to the input shaft and rotates at the same speed. The TCM calculates the input shaft speed to determine the turbine speed.
The TSS uses a magnetic coil. As the input shaft rotates, the sensor detects a pulse signal according to the gear teeth on the outside of the reverse clutch drum and sends it to the TCM.
Vehicle Speed Sensor
The vehicle speed sensor (VSS) detects the parking gear rotation speed. The TCM calculates the vehicle speed based on the parking gear rotation speed.
The VSS uses a magnetic coil. As the parking gear rotates the sensor detects a pulse signal according to the gear teeth rotation speed and then sends it to the TCM.
Intermediate Shaft Speed Sensor
The Intermediate Shaft Speed Sensor (ISS) detects the output gear rotation speed, which is calculated by the TCM.
The ISS uses a magnetic coil. As the output gear rotates the sensor detects a pulse signal according to the gear teeth rotation and sends it to the TCM.