The Alfa Romeo 105 series is designed as a front-engined, rear-wheel-drive car and shares this layout across the series. The front engine drives the rear wheels through a five-speed gearbox, a propshaft and a live rear axle. This drivetrain is comparable in the Giulia, Berlina, GT Bertone and Spider 105/115. As a manufacturer, supplier and spare parts specialist for classic Alfa Romeo models, Alfa-Service carries a wide range of drivetrain components. Individual versions differ by model year and model.
Alfa Romeo 105 Drivetrain at a Glance
The power flow runs from the engine via the clutch and five-speed gearbox to the two-piece propshaft with centre bearing and universal joints, and from there to the live axle with differential. This design was retained across the series, which is why many components fit across models. The most important change is the clutch type, which changed during the production period.
Drivetrain Part Types
The range is divided into the following part types:
- Gearbox and gearbox mounts
- Clutch disc, pressure plate and release bearing
- Clutch actuation (mechanical or hydraulic)
- Propshaft with centre bearing and universal joints
- Live axle, axle shafts and bearings
- Differential and seals
Shared Across the Series or Model-Dependent
The drivetrain is comparable across the series, but there is one important difference: early cars up to 1968 have a mechanical cable clutch and the earlier propshaft centre bearing; from 1968 a hydraulic clutch was used. The actuation, centre bearing and individual connections depend on this. The gearbox is also of the same type across the series but can differ by engine in ratios and ancillaries. When selecting, the clutch type and model year are therefore decisive.
Model Families
For a model-specific selection, the following categories lead to the model families:
Clutch, Gearbox and Axle by Model Year
The most important difference in the drivetrain of the 105 series concerns the clutch actuation. Cars up to 1968 have a mechanical cable clutch; from 1968 a switch was made to hydraulic actuation. The actuation parts, master cylinder and slave cylinder as well as the associated connections depend on this. The propshaft centre bearing was also changed during the production period, so the early and late versions are not identical. When selecting clutch and shaft components, the actuation type and model year should therefore be established first.
The five-speed gearbox is of the same type across the series but can differ by engine in ratios and individual ancillaries. The propshaft is of two-piece design, with a centre bearing and universal joints; at the connections, rubber couplings are used depending on the version. The live axle with differential completes the power flow. In addition there are axle shafts, wheel bearings and seals. The tipo designation also gives a clue: early saloons were partly built with a column gearchange, later ones with a floor gearchange, which affects the gear linkage and associated parts.
The drivetrain components can be divided into clearly defined part types: gearbox and gearbox mounts, clutch disc, pressure plate and release bearing, the mechanical or hydraulic clutch actuation, the propshaft with centre bearing and universal joints, the live axle with axle shafts and bearings as well as the differential with seals. This division helps to put together a complete and matching selection, for example when the clutch kit and actuation are to be renewed together.
As the Giulia, Berlina, GT Bertone and Spider 105/115 share the same drivetrain, many components are comparable across the series. Decisive, however, remain the clutch type (mechanical or hydraulic), engine and model year. Anyone who clarifies these points in advance can assign gearbox, clutch and shaft parts reliably. In case of doubt, a look at the existing actuation and the centre bearing on the vehicle helps.
When sourcing drivetrain parts, it helps to treat the gearbox, clutch, shaft and axle as separate assemblies. Clutch kit parts - disc, pressure plate and release bearing - are usually needed together and must match the actuation type. With hydraulic actuation, the master and slave cylinders are added; with mechanical actuation, the cable and associated parts. At the live axle, axle shafts, wheel bearings and differential seals are typical items that can be assigned specifically once the actuation type, engine and model year are established.
Related Assemblies
The following areas are also relevant:
Notes on Part Selection
What mainly matters is whether the car has a mechanical or hydraulic clutch, since the actuation and centre bearing follow from that. In addition, engine and model year play a role. Checking against the specific vehicle is recommended. It helps to treat the gearbox, clutch, shaft and axle as separate assemblies and to first determine the actuation type clearly. If the clutch kit, the master and slave cylinders or the cable and the centre bearing match the respective version, subsequent parts can be added reliably. As the gearbox is of the same type across the series, many bearing and seal parts are comparable, while ratios and individual ancillaries can differ by engine. This way, drivetrain parts from the clutch to the live axle can be put together as a matching selection without wrong purchases.
FAQ
How is the 105-series drivetrain laid out?
The front-mounted engine drives the rear wheels through a five-speed gearbox, propshaft and live axle. The layout is comparable across the series.
What distinguishes early and late drivetrains?
Cars up to 1968 have a mechanical cable clutch, later ones from 1968 a hydraulic clutch; the actuation and centre bearing differ accordingly.
Are drivetrain parts usable across the series?
Many components are comparable. The clutch type, engine and model year do determine individual parts, however.
Which components are available?
Among others, the gearbox, clutch, propshaft, live axle, differential and bearings and seals.
Is Alfa-Service a workshop?
No. Alfa-Service is a manufacturer, supplier and spare parts specialist for classic Alfa Romeo models and does not carry out repairs.
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