I couldn't find an axle that wouldn't shake or go out in a couple of months... tried a few different brands and various used axles. I finally just stuck with Autozone axles that I would swap out every few months under warranty. Some would end up with split boots or clicking and all caused terrible vibrations on acceleration from the moment they were installed.
So, I finally saved up some cash bought a set of axles from raxles.com... like everyone else who actually solved an axle problem has done. It's like driving a new car now. No terrible shaking at 3-4K or at any other RPMs... it feels so much smoother overall. Yes, they are expensive, but find another axle that actually meets or exceeds OEM specs... these actually have the rubber torque damper rings on them.