I have a set of assembled 4.62 differentials for sale from a 2002 Tracker.  They have 148K on them, are clean and in very good shape.  The air actuator in the front diff is good as well.  Asking $250 for the pair plus shipping cost. 

Are these complete third members?  I just bought an 88 samurai, will these work in it?  Thanks, Chip

Not unless you have a hybrid rear axle housing.  The rear diff gear cluster is too large.  The front 4.62's won't fit into your front carrier because they are too deep.  You could remove the 4.62 R&P from the Tracker carrier and have them set-up into your Sammy carrier but this would most likely also require adding a 'can' to it as well to retain the cross pins because the Tracker/Sidekcik/GV ring gears don't overlap the pins enough to hold them in. 

For a stock Sammy set-up you will want two front gear sets.  I saw on your one link you were planning on running 27" TSLs.  4.30's should provide you plenty of mechanical advantage to pull 27" tires.  4.62s if you want to run 29-30". 

what do you mean by the air acuator ?  will these gears fit into my 97 x-90 front and rear ?

thats what u have.......

The 2nd gen trucks (GVs and Trackers) have an air pump mounted behind the passenger side front bumper connected to the air actuator in the front diff.  When you select 4WD the power is sent to the air pump which pumps 6-8PSI of air to the actuator (an air bladder if you will) built into the front diff which then expands and pushes a metal collar over about 1/4" which gives you the front open diff 4WD.

It is a 'yuppie' set-up that allows operators to engage 4WD without leaving the 'comfort' of the cab.  The down side to the design is that IF either the pump or the actuator in the diff fails... you no longer have 4WD.

As far as fitting into the the X90, they should.  However the Sammy carrier is not deep enough to fit the diff although the bolt holes are the same.  The ring and pinion can be mounted onto the Sammy carrier but would probably require a can to retain the cross pins because the Tracker ring gears don't have a wide enough flange to retain the pins like the Sammy gears had.   

Note: the 2nd gen front diffs are off-set to the passenger side about one inch (because of the actuator design) and IF they did bolt directly into your front carriers....  your axles/CVs would have to be modified accordingly.  If you are just running the 4.62 ring and pinion using your stock carrier... that should work fine.  The rear gears should bolt directly into the X90 axle housing.

Hope this description answers the mail.