I recently bought a standard 2002 f150 and am considering converting it into a 4x4 (currently a rear wheel drive) what would I need to do/ what should I take into account when doing this (besides the "it's cheaper to just buy a 4x4" argument)

 

Find a donor truck for the conversion parts

 

I don't know how the frames are for a 2002 F150, but for the older trucks (80-90's F250's) the frame horns were different between 2wd and 4x4. Having converted my '88 to 4x4, I will tell you it wasn't just a bolt on deal, it took some fabrication to convert from coil springs to leaf springs. While I was able to re-use the rear mounts by drilling a bunch of holes, the front needed quite a bit of modding.

Not only will it be cheaper to just buy the 4x4 truck you want, but it will also save you quite a bit of time.

That being said, if you really like to tinker, and have a good amount of time on your hands, you will want to find a donor truck. Keep in mind you have to swap the transmission, transfer case, both driveshafts, front suspension, and front axle. You may need to do some wiring work to get the 4x4 lights to work, and depending on the style of transfer case, either swap over the lever and linkage, or dink around with more wiring.

Again, this is not quick, easy, and bolt on. Its easier with a donor truck thats the same generation/engine/wheelbase, but you still have a good amount of work to do.

 

Its kind of a trick question anyway, I would say, personally, that the 02 F150 has a torsion bar suspension that isn't the best anyway. I'd totally buy a newer 2wd and convert it, because I think most of the newer independent front suspensions suck it.

But I'm guessing, by your questions phrasing, you just want a nice, clean 02 F150 4x4, as is. In that case, as suggested above, find a rolled or wrecked donor, and swap your body onto it.

 

Unless you're a very experienced fabricator this is NOT a good truck to convert.