My '09 started a strange habit lately. When lowering the (power) driver-side window, it 'jiggles' during the second half of it's travel. It cants forward, then backward, then forward, then backwards...... five or six times until it bottoms out.

I took the door panel off, but couldn't see anything amiss..... for what I could actually see. The glass is a bit loose, but not any more than any other Ranger I've had, and certainly not any worse than the passenger side. If I manage to catch it with my hand before it lowers too far, I can push the glass towards the back and prevent the 'duht duht duht duht duht duht'.

Any ideas what I should look for?

 

Run channel is dry and dirty. Easy way to fix, spray a little lithium grease down the run channel front and rear. Correct way to fix it is to remove the glass, pull the run channel out and clean it properly and apply a light coat of lithium grease or replace it. Oh, you will want to clean the edges of the glass as well. Be sure to clean the rollers and their channel on the bottom of the glass too.

 

I would recommend silicone spray, as it always worked well for me.