1992 Ford Explorer 4wd replacing front drive line universal joints?

[Sam]

Hello, I am 17 and I have basic mechanic skills. Very basic. I have a bad U-joint in front drive line on my 1992 Ford Explorer 4WD. So, I am going to tear into this and I plan to replace all of them with 'greasable U-joints' because NONE of them are greasable. 1. Is this a very tough job? 2. Do I need any special tools? The labor for this is murder if I take it to town to be fixed. I would like to try if you guys think it not a terribly difficult task. Thanks