General Data & Description

The following is adapted from an article in ‘Lanciana’, 1972 (ALC) by the late Tom Sheehan

The clutch, gearbox, transmission & rear brakes of Aurelias are designed as one unit, suspended from the rear floor of the car on four rubber mountings.

The unit changed from model to model but there are two basic designs for overall propelling unit.

The early layout has propeller shaft couplings of segmented rubber ‘spiders’ which are clamped between two alloy flanges with dogs on their inner facings. The flanges are held together by each being clamped to the splined ends of the propeller shaft sections. Alignment of the assembly is performed by small bronze bushings, which are secured to a stub shaft on one flange and whose outside diameter fits inside the centre of the opposite flange. This type of assembly was fitted to all Series I cars – those with the coil sprung rear end - and to B12 and 4th series B20s and B24s - In other words approximately to the end of 1955 production.

On the later cars (B20 S5 and S6 and B24 convertibles) the propeller shaft joints were hexagonal rubber doughnuts bolted between to three-pronged webs at the ends of the shafts. In addition the gearbox was changed to a longitudinally split case and hydraulic clutch actuation was introduced. Top gear is direct rather than the previous ‘overdrive’, and the gear change lever (where fitted) is mounted on the left side of the prop-shaft tunnel rather on the right side of earlier models.

Both systems were fully balanced from flywheel to clutch and the alignment punch marks and weights can be seen on all the components. Wear, misalignment and incorrect assembly will result in awful vibration. The system is very robust, but rough use will produce early wear of the first gear and of the ‘pot’ joints of the rear wheel drive shafts.