It is definitely an adjustment issue. Is the door damaged at all? If the door has been reskinned due to an accident it is possible that some of the adjustment holes (usually the ones on the bottom of the door) are not adequate to get the correct adjustment. If this is a potential issue, you can use a dremel to elongate the holes side to side to get the regulator in alignment. This is a possibility even if the door hasn't been damaged. In many cases, people adjust the regulator as much as possible but it isn't correct and is actually binding. When aligned correctly, the window should roll up and down without binding. This can be a very frustrating endeavor, you really need some patience to get it done. All this said, it isnt rocket science and you can do it. You need to study how it all connects and work, then adjust slowly and deliberately noting what each adjustment does. The main thing with this is that it is not intuitive, you really have to study it as many adjustments do not deliver the effect you think it will.
The teeth grinding off is absolutely a result of misalignment. I would remove the door panel and spend some time rolling the window up and down and try and see where the binding is coming from. Again, don't be afraid to open up a hole or two. Also, make sure all of the hardware is correct, these window assemblies use a lot of unique hardware that over the years has been swapped with incorrect fasteners, lacking important spacers/washers, etc. If you dont have a FSM, down load one and print off the pages on the windows.
As always, come back here and post pictures and ask questions. You will get it, just will take some time.
