Land Rover Discovery Owners & Service Manuals

Land Rover Discovery: Automatic Transmission  Transaxle / Description and operation

Land Rover Discovery (2009–2016) Service Manual / Powertrain / Automatic Transmission  Transaxle / Automatic Transmission  Transaxle / Description and operation


Automatic Transmission  Transaxle / Description and operation

  1. Paddle switches - upshift / downshift
  2. Transmission Control Switch (TCS)
  3. Transmission Control Module (TCM)
  4. ZF 9HP48 Automatic transmission
  5. Automatic Transmission Fluid (ATF) cooler with integrated thermostat


The ZF 9HP48 automatic transmission is a 9 speed, electronically controlled unit manufactured by ZF. The transmission represents the latest in automatic transmission technology for a transverse, AWD (all-wheel drive) unit. The transmission features lock-up slip control, 'CommandShift' functions and automatic and driver selectable modes to give the optimum on and off road performance.

The automatic transmission is controlled by a TCM (transmission control module) which contains software to provide operation as a semi-automatic 'CommandShift' transmission. Driver selections for P, R, N, D and S on the rotary TCS (transmission control switch) are received by the TCM. The TCM operates solenoid valves and clutches to control transmission gear shifts, allowing the system to operate as a 'shift by wire' system, with no mechanical link to the transmission for drive selections.

The TCM allows the transmission to be operated as a conventional automatic unit by selecting P, R, N, D, S on the TCS. Rotation of the TCS to the 'S' position puts the transmission into electronic 'Sport' mode.

Operation of the steering wheel mounted + or - paddle switches puts the transmission into electronic manual 'CommandShift' mode.

For additional information, refer to: External Controls (307-05 Automatic Transmission/Transaxle External Controls, Description and Operation).

The ZF 9HP48 transmission has the following features:

  • Designed to be maintenance free
  • Transmission fluid is fill for life
  • The torque converter features a controlled slip feature with electronically regulated lock-up control on gears 1 to 9
  • Planetary gearset with 9 speeds, 4 planetary geartrains, and 6 shift elements
  • Wide transmission ratio spread with small ratio steps
  • The first-ever use of interlocking dog clutches in a passenger car automatic transmission
  • Shift programs controlled by the TCM
  • TCM has an adaptive capability to ensure efficient gear shift quality throughout the service life of the transmission
  • Diagnostics available from the TCM via the high speed CAN (controller area network) Powertrain systems bus.


 Automatic Transmission  Transaxle / Component Description

The transmission comprises the main casing which houses all of the transmission components. The torque converter is located in a separate converter housing, bolted to the main casing. ZF 9HP48 Cut-Awa

 Valve Block

The valve block is located in a vertical position at the front of the transmission main casing, behind a sealed cover. The valve block contains a number of solenoids and spool valves to control the t

 Drive Clutches

Multiplate Drive or Brake Clutch - Typical Cylinder Piston Disk spring Metal plates Friction plates Baffle plate Pressure equalization chamber Piston chamber There are two multiplate drive


 Playing a portable device

If you are using a USB mass storage device or an approved iPod, you can control playback using the Touch screen controls. If you are using a Bluetooth wireless technology device, you can control playback using the Touch screen, but some controls are unavailable. If you are using any portable media

 Parts and accessories

The fitting of non-approved parts and accessories, or the carrying out of non-approved alterations or conversions, may be dangerous and could affect the safety of the vehicle and occupants, and also invalidate the terms and conditions of the vehicle's warranty. Jaguar Land Rover Limited w

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