Question. I ran into the same sunroof slipping sound on my 2008. Did the most my trick with new bushings. However my issue is that when the gears started slipping originally I didn't notice they only slipped one side more than the other so now my sunroof is cockeyed due to misaligned gears between left and right. . Is there an easy fix without complete disassembly and removal of my headliner/sunroof gears? I can't imagine this being a completely unique problem with such common gears slipping from this motor. When I reassembled the motor I tried to manually shut it with no luck. Now it's stuck closed on one side 1 inch open on the other side.
Accomplished complete removal of the headliner. I put new bushings on all three sunroof motors including pano shade in rear of headliner while it was out. After looking more I saw how the sunroof cables are not "corkscrews" as I thought and can move freely once the motor is removed. A few adjustments with my hands by pulling up on the cockeyed sunroof and I was able to get both sides lined up again before reinstalling the motor. Works excellent and nice and quiet.
I took a few pics and vids of the headliner out since I could not find many for W221 on this. I didn't document my removal and reinstall of the headliner but I would be happy to share any of the details on how to remove all corners and hardware if there is interest. as well as some preventive tricks to lower your frustration (like knowing there are Velcro strips holing the middle and back of the headliner in place. It took about 6 hours total including going very slow and researching as I went.
As always thanks for all the forum experience and great details. I only had to leave BW.org once to see what a "sunroof cable" was for the entire procedure.
High level process:
- Remove all 6 "airbag plugs on each of the pillars (front, middle, rear). they are 8mm bolts
- Remove all headliner handles, front sunvisors, and hook clips. There are torx screws on three items on both sides.
- remove front above console for sunroof and sunglasses by turning the two plastic screws a half turn inside of the sun glass pocket.
- After all headliner screws and airbag bolts have been removed then remove all 4 door's rubber seals around the doors holding all edges of the pillar and headliner ends in place.
- pull the pillars by removing the airbag bolts at the top first, then use a protected flat head screw (or panel remover tool) to pop all the metal clips away from the frame. Outside of the handful of bolts and screws holding the top in place, majority of everything else is pop clips.
- Seatbelt pillars will not come out of the car (since the seatbelt straps to through the center) so just pull the seatbelt out enough to lay them both in the back seat.
- The rear pillars have the airbag 8mm bolts plus one torx screw behind the rear privacy window track (the plastic track pops out exposing the torx screw). Taking out this screw and removing one of the read deck side pillar panels was the only way I was able to get the entire headliner to drop. once you remove the two rear pillar panels the headliner is only held in by the velcro strips and a few clips.
- when you have all pillars removed and all hardware detached from the headliner, then you can pull the snap clips away from the sunroof and begin to remove the velcro strips holding the center and rear of the headliner in place. You do not have to remove the rear vanity mirrors nor the rear parking sensor, they will come down with the headliner once the velcro strips are pulled apart.
- reverse procedure to install. The velcro strips are your friend when trying to re-position the headliner for installation. Start at the rear, get it line up with the velcro, then you can use the middle velcro strips to hold the headliner up without needing to hold it yourself.
- one note... the headliner is too heavy for itself. If you don't properly lay it on your front seat head rests then you can accidentally have it fold down on itself causing creases in the headliner. Be sure to prevent this by propping it up in the front seat with something while it is not attached. I used an aluminum pole with pads on each side. The rear deck and front headrests will balance about 60% of it but you have to prop up the front to be safe.
Slow and patient and you damage zero and get nothing dirty.