I second what alabamafrog wrote. If you Google "Guzzle PSD" he has a website that has a bunch of maintenance and mod instructions. One of those is to clean your auto hubs. You should also engage and drive in 4x4 at least once a month to keep the system properly lubed and running correctly otherwise you can freeze your hubs or have other parts not work correctly either.
I just went through that fiasco. I had vacuum leaks (yes, leaks) and a failed solenoid. I had the chance to get the Warn Premium Hubs, but decided against it. I don't rock crawl and I want the convenience of engaging from the comfort of my cab. I don't want to get out and lock them in bad weather or mud. Right now you're saying I can just lock them before I leave for the day and unlock them at the end of the day. I don't engage 4wd the whole time I'm off the pavement and would prefer not to spin the axles for a couple hundred miles without the transfer case engaged. All you guys in the Great White Mid-West are yelling at the screen saying you have yours locked for 7 months out of the year and you don't have any problems. Call me cautious, but I've got 152k miles and I'm on the original ball joints, transmission and everything else (knock on wood) and will be as nice to my truck as possible to get another 150k out of it. Okay, so the hubs aren't original. I lied, sue me.