I'm attacking all the interior components of the power rear window mechanism this weekend on my 91 K5. All the channels and tracks are completely rusted away. My question is, does the window just sit in the bottom sash with the new rubber film, or do I goop it all up with weather stripping adhesive? I know gravity pretty much does all the work, but the window looks like it can pull out of that sash pretty easily. Any info is appreciated.