Jaguar XJ (X350). Manual — part 1040

1 planetary gear carrier

1 ring gear

Double Planetary Gearset

Item

Part Number

Description

1

Planetary gear spider brake D

2

Planetary gears (short)

3

Ring gear 2

4

Output

5

Double planetary gears (long)

6

Planetary gear spider clutch E

7

Sunwheel 3 clutch B

8

Sunwheel 2 clutch A

Apply Components

Shift Elements

The other shift elements in addition to the torque converter lock-up clutch are:

three rotating multi-plate clutches A, B and E.

two fixed multi-disc brakes C and D.

All gear shifts from 1st to 6th or from 6th to 1st are power-on overlapping shifts, that is to say during

the shift one of the clutches must continue to transmit the drive at lower main pressure until the

other clutch is able to accept the input torque.

The shift elements, clutches or brakes are engaged hydraulically. The transmission fluid pressure is

built up between the cylinder and the piston, this presses the clutch plates together.

When the transmission fluid pressure drops, the cup spring pressing against the piston moves it back

to its original position.

The purpose of these shift elements is to perform in-load shifts with no interruption to traction.

Multi-plate clutches A, B and E supply power from the engine to the planetary gear train; multi-disc

brakes C and D bear against the transmission housing in order to achieve a torque reaction effect.

Shift Elements

Item

Part Number

Description

1

Multi-plate clutch B

2

Clutch cylinder B, outer plate carrier

3

Multi-disc brake C

4

Brake cylinder C, outer plate carrier

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5

Shaft key

6

Brake cylinder C, outer plate carrier

7

Transmission housing

Multi Plate Clutch

Clutch E is equalized in terms of dynamic pressure, that is to say its piston is exposed to the

transmission fluid flow on both sides, in order to prevent pressure build up in the clutch as the speed

increases. This equalization process is achieved by a baffle plate and pressure-free transmission fluid

supply by a lubricating passage, through which the space between piston and baffle plate is filled

with transmission fluid.

The advantages of this dynamic pressure equalization are:

reliable clutch engagement and release in all speed ranges.

improved shift refinement.

Multi Plate Clutch

Item

Part Number

Description

1

Lubricating transmission fluid passage

2

Turbine shaft

3

Main pressure supply to clutch E

4

Ring gear

5

Cylinder E

6

Piston E

7

Cup spring

8

Clutch plate cluster

9

Baffle plate

10

Space for dynamic pressure equalization

11

Inner plate carrier E

Shift overlap control

When overlap gearshift takes place, freewheels (one-way clutches) are not used but are replaced by

suitable actuation of the relevant clutches. This both enables weight and space to be saved.

The electronic-hydraulic shift action is obtained by means of various valves in the transmission

control module (TCM) and main control valve body, actuated by pressure regulators. They engage or

disengage the relevant clutches or brakes at the correct moments.

Output is always by the ring gear of the second, downstream planetary gear set.

Hydraulic System

Fluid Pump

The fluid pump is of a "half-moon" pattern and delivers approximately 16 square cm of transmission

fluid per revolution.

It is located between the torque converter and the transmission housing.

The torque converter is supported in the fluid pump by a needle roller bearing. The fluid pump is

driven directly from the engine by the torque converter shell and supplies transmission fluid to the

transmission and the hydraulic control unit.

The fluid pump draws in transmission fluid through a filter and delivers it at high pressure to the

main pressure valve in TCM and main control valve body unit. This valve adjusts the pressure and

returns excess transmission fluid to the fluid pan.

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