Manual gearbox - Getrag (Description): Description and operation

Description

General

The Getrag 283 manual transmission incorporates a three shaft configuration, including a dual mass flywheel and a concentric slave cylinder, designed and manufactured in conjunction with Getrag. The gearbox is assembled in a purpose built factory in Bari, Italy.

The gearbox is of a 5 speed constant mesh type with all gears being of helical form.

Reverse gear noise quality matches the forward gear performance by including helical gearing. The dual mass flywheel is used to eliminate torsional vibration noise.

Unusual compactness is achieved by utilising the 3 shaft arrangement, this allows 1st/2nd and 5th/rev synchronisers to overlap as well as 1st and reverse gears to share components and take half the length usually required.

The Getrag 283 gearbox benefits from increased refinement for several reasons including the fact that all gears are power honed or ground after heat treatment in order to reduce distortion and optimise gear geometry achieving smooth quiet running.

To help improve the overall gear change quality, double cone synchronisers are used for 1st and 2nd gears to reduce load and improve smoothness into gear, whilst 3rd/4th and 5th employ single cone synchromesh, Reverse gear synchromesh is also specified.

The oil used in the gearbox is MTF94 which is exceptionally stable under wide thermal extremes and has a very high service life of 100,00 miles giving it improved durability.

For the Freelander a more efficient rod type gear change is specified.

There are also switches located on first and reverse gears to electronically let the gearbox know that 'Hill Decent Control' (HDC) is enabled if engaged by the driver.

To allow the application of four wheel drive the output from the gearbox is transferred to the Intermediate Reduction Drive, (IRD) by means of a final drive carrier.