I have a 92 2wd Tracker, if I get a 4x4 drive train is it all "bolt in"?
 
 

I have heard that you need to weld in a front diff mount...

Some 2WD Frames have the Drivers Side mount, and some don't.
I converted a 2WD that didn't have the bracket, I built one from
1/8th inch plate and welded it into place.

You can use the 2WD cross member,(if I remember right) but you
need the t-case mounts to get it all hooked up

Wild

You will need the drivers side frame mount for the front axle drop bracket.....I believe 96 was the first year that had both of them already.  You will also need the 4wd crossmember.
Here is all the details on a swap that I did......
http://bbs.zuwharrie.com/content/topic,104321.0.html

I used the 2WD tranny, took the tail housing off and bolted the t-case
up to it, no problems.

Thanks guys.

Someone listed a 4x4 drive train on craigslist & it got me thinking  .  I have a rusty Samurai with a plow & am looking for a 4x4 Tracker to put the plow on.  But the ad got me thnking.

I have done this mod. a few times. Cut off the front diff. mount from wrecking yard 4X frame & re-welded. Cross member & mounts, new front drive shaft & rear as 2X it too long. Londer speedo cable is needed & get ready for that as it enters the pass. side of the dash & runs behind the stereo to your speedo. (Not fun). No 4X light unless you pull speedo head & run the wires. Inside transfercase shifter boot assm. & don't forget both case vent lines if you want to get muck out of your new install. Yea, the diff. axles, hubs & mounts will be a bolt it.