184000306 - INTRODUCTION - GEARBOX

CONSTRUCTION FEATURES

Manual gearbox positioned transversely in the engine compartment, including 3 shafts supported by bearings with the gears always meshed and a final drive reduction. The twin cable external control is made from plastic materials with excellent properties (resistance to fatigue, self-lubrication capacity, reduced weight).

The following different types of gearboxes are adopted according to the engine type:

C.514 5 speed gearbox for 1.2 16v and 1.4 16v;
C.510 5 speed gearbox for 1.3 JTD;

1, Manual gearbox with differential2, Manual gearbox external controls2, Speedometer sensor

GETRAG GEARBOX

Specifications

The Stilo version with a 1910 jtd 100 bhp engine is fitted with a new generation Getrag gearbox coded: C538.

Main gearbox features are as follows:

takes up less room at either side
excellent manoeuvrability at all speeds
very low noise levels.

Gearbox configuration is transverse with 3 shafts and an internal differential. All gears come with HRC teeth that are superfinished after heat treatment.Gearbox and clutch housings are computer-modelled (FEM/FINITE ELEMENT METHOD) to achieve the lowest weight without affecting strength.The gears are all synchronised, including reverse, and synchroniser rings are all brass coated with molybdenum and are the Borg Warner type.First and second gears, including synchroniser rings, are fitted to an idler shaft between the main and layshafts.The synchroniser gear set for third and fourth speeds is fitted on the mainshaft while the fifth speed and reverse sets are on the layshaft.The synchroniser rings on the most frequently used gears, i.e. the first and second speeds, are double done to ensure lower engagement effort than with a conventional synchroniser or one with a single ring.The internal gear control system is designed over three selection planes, with a central gear positioner mounted on bearings.The clutch control is hydraulic with a coaxial CSC system coaxial on the mainshaft inside the gearbox.The gears and drive chains inside the gearbox are lubricated dynamically by channelling oil flows through holes in the casings and on the mainshaft and layshaft and also through additional plastic channels; all this allows improved torque transmission efficiency and more effective wear prevention. This system has a clutch plate wear recovery device that allows the force on the clutch pedal to be kept constant during the working life of the vehicle.

The advantages of this system are as follows:

improved acoustic comfort
reduced shift effort
lever free of vibration and shudder.

Transmission of drive in different gears

First speed

The drive entering from the main shaft, is transmitted to the intermediate shaft via the synchro engagment and 1^st speed gear (on the intermediate shaft). The 3^rd speed gear (on the main shaft and currently in 'neutral') allows the transmission of the drive from the intermediate shaft to the layshaft and then to the differential, thereby completing the kinematic chain for first speed.