So... it would seem anyone saying they have changed out this switch in under 10 minutes are prone to hyperbole, no matter if they went from the top or underneath (I did both). Even if all the planets were aligned, someone had done this many times before, and nothing went wrong while doing it, I really don't think you could do this in 10 minutes. That said, it's not too difficult, it should just be noted that 10 minutes is certainly an exaggeration. I wanted to post a couple of things that should make this an easier process for those who come after. First, the wire connector that attaches to the actual switch (what you will replace) comes off by pressing the flat part closest to the wires. It's a lever retaining clip, and when you pinch at the wire end it will allow the connector to come off the switch. The switch is in the shape of a 1 1/2" nut, thus you can use a 1 1/2" socket to remove it, but it will need to be a shallow socket (not a deep well), because there is NO space in there for a deep socket. My socket set tops out at 1 1/4", so I just used a channel lock. After just barely twisting the switch with the channel locks, I was able to finish unscrewing the switch by hand; a couple times I had to give it a little extra oomph with the channel locks, but I was able to do it mostly by hand, which is good since there is VERY little room to work in there. The "o-ring" at the base of the threads on the switch isn't really a typical o-ring. It's more of a gasket (a flat piece of rubber, not a rounded ring). This thing is there to keep crud and moisture from getting inside the switch from underneath the vehicle, which is probably why your switch failed in the first place (even with the gasket there). This gasket will obviously help, but contamination can still enter the switch from inside the t-case (where the plunger is for the switch). The biggest reason I'm posting: when I was putting everything back together to test the switch, I found that my 4wd shifter was just flopping around. Turns out the shifter cable slips over a pin on the transfer case arm and is held in place with a retaining clip. My clip is gone. It's not on the ground, and judging by the plastic washer on the inside of the cable loop that slips over the t-case pin (between the loop and the t-case selector), I think it probably deteriorated and fell off a while ago, and the cable has been hanging on by tension alone. Now I need to figure out what kind of retaining clip to use to keep the cable attached to the t-case arm so the shifter will work again.