Just got my car a few days ago, so I don't know if this sound is normal or unusual. Does your power liftgate sound like this when opening or closing? https://m.flickr.com/#/photos/[email protected]/17261353073/
Had this happen to my early 2013 S60. Service center fixed it; they replaced the gas struts, if I recall right.
mine was much worse than this and they replaced the motor which is actually built into the (IIRC) right strut. the left strut is just a strut, not motor. The sad part is the new motor is starting to sound labored like the old one... I do use the lift gate a good bit (probably around 4-5x per day) with one usage being up and down.
I realize this is an old thread but it fits my question. My lifgate just started making this exact noise. So since this is from last year did you have to have the strut replaced again? I'm wondering if I just live with it or is this an indication of imminent failure? Out of warranty so this will be out of pocket.