i disconnected battery first too just to be safe.
Mine creaked and rattled, so I took off the roof rails and trim and gave all the tracks a really good clean with WD40, kitchen roll and cotton buds, followed by a good squirt of white grease. I also hoovered out then polished all the surrounding areas (before greasing). It's been pretty quiet ever since, and also slides much nicer. Although it still needs a gentle manual assisting pull when it's closing.
I wouldn't seal it shut unless it leaks. The worst case would be to glue it shut and then find it still rattles. Then you're stuck.
I agree - driving with it open is horrible. I only tilt it (the first click) when the car's been parked and is really hot, just until the air con shoves all the hot air out of it. The tilt works great, it's only the sliding that sounds a bit strained.
Looking at the mechanism, it's obvious why it struggles. There are no rollers or bearings etc, just lumps of plastic getting shoved along a metal track. It was never going to work well.
Mine gets WD40'd to the hilt every couple of weeks.
Works lovely.
(So, I'm fully expecting a catastrophic failure tonight now)
It's worth it