Parts for your 2018 Subaru Forester-Universal joints

2018 Subaru Forester universal-joints

Based on the Subaru service manual for the SJ-series Forester (2018) and OEM parts catalogues covering the propeller shaft assembly, this model uses cross-type universal joints (U-joints) on its two-piece rear propeller shaft, along with a centre support bearing. That setup is typical for Subaru’s longitudinal “Symmetrical AWD” driveline, where the transmission/transfer section sends drive to the rear differential via a shaft that needs to articulate with suspension movement and body flex.

On a 2018 Forester, the U-joints let the prop shaft run smoothly as the angles between the gearbox and rear diff change. They keep the rotational path steady, reduce binding, and help prevent vibrations. While front and rear drive axles use constant-velocity (CV) joints at the wheels, the prop shaft between the gearbox and rear diff relies on U-joints for compactness and reliable angular motion.

From factory, the Forester’s U-joints are sealed and not greaseable. That means there’s no scheduled greasing during routine servicing, but inspection is still smart. A mechanic should check for play at the joints, look for rusty “brinelling” dust around the caps, and listen for chirps or clunks on take-off. If there’s vibration under load at highway speeds, shudder when selecting Drive/Reverse, or a rhythmic squeak that follows road speed, the U-joints or centre bearing could be on the way out.

When replacement is needed, Subaru generally supplies the propeller shaft as a complete assembly because the original joints are staked in. Some driveline specialists can fit quality circlip-style replacements and balance the shaft, but many workshops will recommend swapping the whole assembly for reliability and time. Either way:

• Mark flange positions before removal to keep phasing/alignment correct.
• Use new flange bolts where specified, apply thread locker if called for, and torque to the workshop manual.
• Check the centre support bearing and mount while you’re there.
• Road-test for vibration and recheck fasteners after a few kilometres.

For owners who tow, tour rough roads, or see lots of river crossings, more frequent inspections are worth it. Keep an ear out for new noises, and sort any driveline vibration early to avoid collateral wear on the diff, transmission mount, or centre bearing.

Popular questions

Does the 2018 Forester have grease nipples on its U-joints?
No. The factory U-joints are sealed, non-serviceable units. There’s nothing to grease at routine services. If a joint wears out, most workshops will fit a complete prop shaft assembly, some driveline specialists can retrofit serviceable U-joints and then re-balance the shaft.

How long do the U-joints typically last?
Plenty of Foresters see 150,000–250,000 km on original U-joints, but lifespan depends on use. Frequent towing, corrugations, or water/mud exposure can shorten service life. Regular inspections for play and noise help catch issues before they cause vibration or damage to the centre bearing.

What’s the difference between the Forester’s U-joints and its CV joints?
CV joints live at the wheel ends on the front and rear axles, handling big steering and suspension angles with constant speed. U-joints are on the propeller shaft between the gearbox and rear differential, allowing angular movement with a compact design. Different jobs, different designs—both crucial to the AWD system.