Have you tried lubing the pivot joints? Mine were getting slow so I hit them with some silicone spray. They're still not the fastest things out there, but they move smoother and are a little quieter. I thought about taking them apart to grease the motor, but the write up I found was a little extensive for my current level of motivation.

 

Take a look @ 1AAuto.com - they may have something that works with your truck.

 

I need a plastic trim piece for my passenger side mirror. I don't recommend backing into the 4" metal support pole for 14' swing gate (7' each side.) I checked with the dealer on Monday when I was there buying a window regulator.

The entire mirror assembly is listed at $1279. Ouch. I can't get the trim piece I need but he did say the motors are available separately. So maybe there is hope for after market motors as well. I'm hoping I can find one in a wrecking yard. Since mine still work fine I'm not in a huge hurry. I broke it a year ago anyway.

In my 2015 it's pretty easy to take the mirror assembly off. I haven't dug inside it, but there should be a Youtube video somewhere. Good luck with this. Let us know what you find.