Land Rover Defender: Component Location, Overview

COMPONENT LOCATION

COMPONENT LOCATION - 1 OF 2 - AUTOMATIC TRANSMISSION

1. Emergency Park Release (EPR) lever
2. Automatic transmission
3. Automatic Transmission Fluid (ATF) cooler pipes
4. ATF cooler

COMPONENT LOCATION - 2 OF 2 - TRANSMISSION CONTROL

NOTE: Right Hand Drive (RHD) variant shown, Left Hand Drive (LHD) variant is similar.

1. Transmission Control Switch (TCS)

OVERVIEW

The 8HP76 transmission is an electronically controlled, hydraulically operated, 8 speed automatic unit. The 8HP76 transmission is similar in design to the 1st generation 8HP70, but has the following major differences:

Disc Separation

Wave springs integrated within the transmission shift elements allow for improved drainage of ATF back to the transmission fluid pan. This reduces drag across open shift elements for improved efficiency.

Spool Valve Mechatronic

Increased use of the finer tolerance spool valves in place of 8HP Gen 1 transmission poppet valve technology improves the efficiency of the transmission hydraulic circuit.

90% Mechanical Vane Pump

The mechanical vane pump is a comparable technology to the 8HP Gen 1 transmission, with a reduced pump volume.

The smaller pump volume reduces pumping losses when still meeting the pressure demand due the improved hydraulic circuit efficiency due to increased use of spool valve technology.

Optimized Brake B

A new piston design offers increased controllability for higher shift quality, as well as improved drainage of ATF back to the transmission fluid pan, which reduces drag across open shift elements for improved efficiency.

Wider Ratio Spread

The new transmission ratios are better matched to customer demands for improved low speed ascent vehicle capability and improved vehicle efficiency.

The 8HP76 transmission has the following features:

• Designed to be maintenance free.
• The ATF is 'fill for life'.
• The torque converter features a controlled slip feature with electronically regulated control of lock-up, creating a smooth transition to the fully locked condition.
• Shift programs controlled by the Transmission Control Module (TCM).
• Adaptive Shift Strategy (ASIS), to provide continuous adaption of shift changes to suit the driving style of the driver, which can vary from sporting to economical.
• Connected to the Powertrain Control Module (PCM) through the FlexRay systems bus for communications.
• Default mode if major faults occur.
• Diagnostics available from the TCM through FlexRay systems bus.

On vehicles featured with the stop/start system, the 8HP76 automatic transmission is equipped with a Hydraulic Impulse Storage (HIS). The HIS device makes sure that pressurized ATF is available to the shift elements as quickly as possible when the engine is started.

The transmission selections are made using the TCS in the floor console.

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