Parts for your 2018 Subaru Outback-Centre bearing

Centre-Bearing on the 2018 Subaru Outback: Is It Relevant?

The 2018 Subaru Outback is a popular all-wheel-drive vehicle known for its reliable performance and rugged versatility. When it comes to its drivetrain layout, enthusiasts and owners often wonder about the presence and role of a centre-bearing. After reviewing technical sources, service manuals, and Subaru's engineering approach, it turns out that a centre-bearing is not used in the 2018 Subaru Outback.

This absence is primarily due to the vehicle's symmetrical all-wheel-drive system and its drivetrain configuration. The 2018 Outback utilises a relatively compact driveline design that doesn't require a centre support bearing. Its driveshaft setup involves shorter shafts driving from the transmission to the rear differential without the need for an intermediate support bearing. On vehicles with longer driveshafts or multi-piece shafts, a centre-bearing is often employed to support the shaft along its length and reduce vibration, but the Subaru Outback's drivetrain geometry minimises the need for this.

More specifically, the Subaru Outback features a direct connection from the transmission/transfer case to the rear differential via a solid shaft or propeller shaft. Because this shaft is short enough and well-supported at both ends, it does not suffer from the kinds of flex, imbalance, or vibration issues that would necessitate a centre-bearing. Additionally, Subaru's unique flat-four "boxer" engine design and balanced all-wheel-drive axle layout help keep the drivetrain smooth and stable, further removing the need for an additional bearing support.

So why do other vehicles have centre-bearings, and why might it seem like the 2018 Subaru Outback should have one? In many four-wheel-drive or rear-wheel-drive setups, especially those with longer or two-piece driveshafts, a centre-bearing plays a crucial role. It supports the centre of a long driveshaft, allowing it to be subdivided into parts that are easier to manufacture and handle. This bearing reduces shaft vibration, prevents bending, and absorbs forces that would otherwise wear down joints and mountings. On large trucks, vans, or models with significant driveline length, it is common to find this component.

Since the 2018 Subaru Outback's design avoids the need for a centre-bearing, owners do not have to worry about this part for their regular maintenance. Instead, attention is focused on other driveline components such as the CV joints, differentials, and fluid changes to keep the all-wheel-drive system running smoothly.

That said, it is worth briefly discussing the purpose and servicing advice for centre-bearings generally, because this helps Subaru owners understand drivetrain components better, especially if they compare the Outback to other vehicles in the same class or consider aftermarket modifications.

A centre-bearing typically consists of a rubber insulated bearing cartridge mounted on a support bracket fixed to the vehicle's chassis. Its main job is to support the middle section of a multi-piece propeller shaft and isolate vibration between the shaft and the chassis. It encourages driveline longevity by reducing the stress on universal joints (U-joints) or CV joint assemblies.

When a centre-bearing goes faulty, symptoms often include noticeable driveline vibrations, clunking noises when accelerating or decelerating, and sometimes a harsh or rough ride. This is because the bearing reduces movement that would otherwise cause excessive wear or misalignment. If not addressed, a defective centre-bearing can lead to the failure of connected drivetrain components, resulting in costly repairs.

For vehicles that do carry a centre-bearing, maintenance involves regular inspection during service intervals. This includes checking the rubber mount for cracks or deterioration, ensuring the bearing spins freely without grinding, and confirming the support bracket is securely fastened. Replacement is generally recommended at the first signs of wear because the cost and complexity usually increase if left too long.

If the 2018 Subaru Outback owner ever encounters driveline vibrations or noises, the focus should be on other components like the CV joints or the rear differential. Proper lubrication and quick attention to worn bushings or mounts will keep the drivetrain healthy.

In sum, while the 2018 Subaru Outback does not use a centre-bearing due to its efficient and compact AWD setup, understanding how and why this part functions on other vehicles can help owners appreciate Subaru's thoughtful engineering choices. Regular servicing aimed at the components the Outback actually uses will ensure a comfortable, reliable ride no matter where the road takes you.