Bad smell when window rolls up


I have a breathing disability and am very sensitive to odors. When I roll up the drivers window, just at the time it closes, it seems like it creates a little suction then, and an odor of grease fills the cab of my nissan pickup. I cant find where it is coming from, and it really irritates my breathing for a few seconds, then it seems to dissipate. I had the shocks changed many months ago as someone said they were leaking, thought that was it, but no. Ive cleaned the bottom of the stick shift inside the cab only, under the black vinyl cover, it had a little grease on it, but no improvement. Any suggestions appreciated…thanks