My '96 855GLT has a slow driver's side window down function which only takes the window down about 1/2 way. The mirror adjustment on the driver's side has become very limited as well. Is this likely the switch or the motors driving these parts? Everything else operating from he switch cluster seems ok.

 

I would guess it's in the door somewhere. The switch is either on or off - if you press it softer or harder, it doesn't change the speed in which the window drops.

I would start by opening the door and inspecting the window guides, etc. Over time, the lubricants used in window channels, felts, etc dries out and gums up. At least, I've seen this on other makes.

 

Also the rear guide rail for the window is known to break. The mirror motor (there are 2) could also be broken, better said the plastic rails which are moved by the 2 motors. Take the mirror glass off and look at the mechanism

 

 

I removed the door panel and tested the window only to find that it worked perfectly without the door panel. When I put the panel back on, the window returned to only going 1/2 way down. I loosened the screws on the bottom door edge a little, and got it to go down the whole way. My question is, where/how do you lubricate the moving parts? I couldn't find any. Also, how do you lubricate the rubber at the top of the panel without getting some kind of residue on the glass? Thanks.

 

The top weather strip should NEVER be lubricated. It has felt material on it and it should not grab the glass.

You should be able to see the window regulator in the door to lubricate it. Did you remove the plastic from the door skin?