Drivers side window (power) will go down about 4 inches then stops. I hear a grinding sound like gears not meshed. Wont go up unless I assist by hand. Passenger side window works fine

the guides are bad, replace them.
the noise tells this.

Since you have power, once in a while, the fuse must be good. Sounds more like a faulty ground connection. Check all body ground connections on the doors and under dash. Therein lies your problem. When something electrical goes south on me, I ALWAYS check grounds FIRST. That's normally always the answer.

I would say the noise is the gears over-running each other. There is a gear on the motor and one on the window regulator.
You probably have a restriction in one of the tracks.

probably need torque converter worked on. can you get it in gear before you hear the gears grinding, or does that happen after you have it all way in gear?

its a bad window regulator

SOUND LIKE WORN OUT GEARS.GEARS WORN TO A POINT WHERE THEY MESH TOGETHER.INSTEAD MESHING GEARS GRINDING GEARS TEETH WORN WHERE THEY DONT MESH ANYMORE THEY ARE TEETHLESS.

IF there is a grinding noise then the motor is trying to move, so take out he unit and try to see if the motor works , if so the mechanism is faulty or the motor does not have power in the drive.
can be the driver switching the motor or the motor itself. Replace after testing the transistor drive.

sounds like your sun roofs gear or track is stripped. Replace the motor for the side window had the same problem there really cheap.

Sounds like the stop for the window broke or the window traveled too far down and the gear no longer is engaged with the window rack gear you will know when you remove the door panel be careful with the panel clips the break easily

It sounds like either your window motor is bad (gear failure), the window regulator is out of alignment or a combination of both. I'm leaning towards the motor because I had the exact same problem and it turned out that my window regulator was binding which caused the motor assembly to fail. They sell them together or separated. It's not the easiest tast to accomplish but not the hardest.