i have 2000 Silverado and you will be better off replacing entire regulator. I had both replaced roughly at 60K miles.
there's really nothing to it.
1/ go to library copy page from Haynes or Chilton
2. go online Autozone/repair manuals
3. buy manual, as you will need it anyway, have my word on it. only about 15 bucks.
regulator is attached to door frame with 4 bolts, covered by plastic. glass is connected to regulator with 2 bolts, you need to lower glass to expose them. there will be 2 openings in frame that will allow you to access those bolts. you will need one of those flexible grabbers, with little prongs coming out when you press the button, as you WILL lose drop at least one of nuts.
i used to tape glass to the outside door panel using masking tape, so that it does not fall down when you remove regulator.
you disconnect regulator, pop it off the frame, fold it it together, and wiggle out through frame opening. last time i did one, took me only about 10 minutes.
aftermarket regulators are around $60 each online, and work very well.