Parts for your 2009 Subaru Forester-Universal joints

Are Universal Joints Used on the 2009 Subaru Forester?

When it comes to the 2009 Subaru Forester, universal joints are not a part of its drivetrain design. This might come as a surprise to some, especially if you are familiar with the typical use of universal joints in many rear-wheel-drive or older four-wheel-drive vehicles. However, the 2009 Forester uses a different kind of setup that makes universal joints unnecessary.

Universal joints, often called U-joints, are mechanical components that link driveshafts, allowing them to transmit power smoothly even when they are at odd angles. These joints are quite common in vehicles with traditional rear-wheel-drive or certain four-wheel-drive systems that use a solid driveshaft running from the transmission to the rear differential. They help accommodate the movement of suspension and the relative angles between the connected shafts. But when you consider the 2009 Subaru Forester, it features a full-time all-wheel-drive system that is fundamentally different.

The 2009 Forester employs a symmetrical all-wheel-drive system paired with a horizontally-opposed boxer engine. Instead of a long driveshaft running to a rear axle, the vehicle uses a system where power is distributed through a series of compact drive shafts that connect the transaxle directly to each wheel hub. This layout uses constant velocity (CV) joints instead of universal joints.

CV joints are designed to transmit power smoothly while handling a variety of angles, particularly those introduced by steering and suspension movement. They provide better control and less vibration at higher operating angles compared to U-joints. Because the Forester's AWD system and the design of its drivetrain shafts require joints that allow for consistent rotational speed and smoother power delivery at sharper angles, CV joints are the preferred solution.

So why are universal joints not used in this case? It mainly comes down to the packaging and the mechanical demands of the vehicle's AWD system. Universal joints tend to cause speed fluctuations at higher angles, which can translate into vibration or jerky movements. On the other hand, CV joints are specifically engineered to maintain constant velocity of the shafts regardless of angle, making them much better suited to front and all-wheel-drive vehicles where the wheels not only receive power but also steer and move up and down with the suspension.

Ultimately, the 2009 Subaru Forester does not require universal joints because the drivetrain architecture is focused on smooth power delivery through CV joints, mounted on shorter drive shafts that accurately handle the movement and steering requirements of the vehicle's AWD system.

Knowing this is important for maintenance and servicing. Instead of worrying about universal joints, Forester owners should pay attention to the CV joints and drive shafts, which are the parts that undertake many of the same roles in transmitting power smoothly and reliably under all the conditions that the vehicle encounters. Checking for wear, boot damage, or grease leaks on CV joints is key to maintaining the health of the drivetrain and preventing costly repairs down the track.