Creaking noise left rear knuckle --Gen 6 3.6R

[irasend]

My 2015 Legacy 3.6R recently developed a nasty creaking noise coming from the left rear wheel.  Happens with any up and down movement of the left rear wheel eg. getting in or out of the car. any uneven road etc. Got underneath and sounded like it was coming from the lateral link. Changed the bushing without improvement. Any thoughts?

[silverton]

It takes two people, but while you lay under the car with a can of wd40, have someone else bounce the car enough to make the noise happen, and start spraying the bushings and other pivot points. Once the noise is gone you've found the culprit.

[irasend]

So after much trial and error, the noise seems to be coming from the knuckle at the attachment to the lateral arm.  How common/difficult is it to change out that knuckle bushing? Is it available after-market or do I need to get one from Subaru? In my diagram it is called the rear axle housing bushing.