I don't know if the Tracker is 2 or four door or if it is auto or manual.  Any clues?  Thanks for your help.

Nope! 

You can swap it into the front of a Sammy though.  The 94 has 22 spline, same as the SJ in the front.  If you talk to Low Range Off Road, Hawk Suzuki or Trail Tough they can send you a diff can that will allow you to install the 5.12 gears into the SJ carrier.  Then you can user your side gears/lockers that are already installed.

I'm more of a fan of going with Transfer Case gears before the axles myself.  Only do the axles if you need even more of a downgrade.

I don't know if the Tracker is 2 or four door or if it is auto or manual.  Any clues?  Thanks for your help.

As the other poster said, yes, you can swap the ring and pinion out of any TracKick FRONT differential into both the front and rear Samurai differential using a swap kit designed for this purpose.  HOWEVER - if you have a 4wd Samurai it is ESSENTIAL that you swap both the front and rear difs at the same time with the same ratio gears!  Most of the aftermarket parts vendors that advertise on this website sell the kit.

To find out what difs are in a '94 Tracker or Sidekick, do a search for differential at Ack's FAQ (the link is in my signature).  The third result item - Skyhiranger's Table of Factory TracKick Body/Engine/Transmission/R&P Combinations has the information that you are looking for.

I hope that this helps!

I'm new to the zuki, so I appreciate all of the great info.  I have know for years that the gear in front and rear need to match, I'm just trying to get gears one peice at a time.  I have been looking into just transfer case gears as my needs are pretty simple, and this will not be a rock crawler.  I am putting flat top pistons in a .040 over block with every thing else stock.  I'm installing a 3 ' Calmini spring lift and want to put 235-15's on it.  With that said, what transfer case gearing would allow decent low 4WD performance and perhaps be able to do 65 mph in 2 high on the highway?  Is 65 mph asking too much?  Thanks again for all of the great info!

Back to the 5.12 R & P, I just want to put the ring and pinion from that donor vehicle into the 87 sam carrier.  I take it that is what the swap kit is all about?

With only 30" tires a 4.8:1 should be plenty.   

I changed my user name to IdahoZuk. 

"With only 30" tires a 4.8:1 should be plenty."  Great answer.  Thanks!