2000 and up North American UZJ100's don't have rear differential locks. They have ATRAC and VSC.
Here are the differences between '02 and '03 (Taken from the Slee Off-Road website).
Drivetrain
* Engine Output increased to 235hp
* Changed to a drive by wire with an accelerator position sensor on the accelerator pedal
* An A750F 5 speed automatic transmission was added
* Rack and pinion steering was changed to Variable Gear.
* The throttle position sensor was changed to a no-contact unit.
* Charcoal canister capacity increased and moved to above the spare tire.
* Shift pattern for transmission was changed to a gate type.
* The front and rear driveshafts were updated with stronger U-joints and larger tubes
* Propeller Tube Diameter ’03 Model (A750F) ’02 Model (A343F)
Front 65.0 mm (2.6 in.) 54.0 mm (2.1 in.)
Rear 75.0 mm (3.0 in.) 65.0 mm (2.6 in.)
* The differential gears were changed to a 4.1 ratio.
* The tow hitch was offered as optional equipment
* The rear cross member was changed to accept a towing hitch that can be bolted to the rear cross member.
* Catalytic converters were changed
* Radiator fin pitch was changed for better cooling
* Alternator was changed to a high output segment conductor type
* Fuel cutoff switch when airbags are deployed was added
* Crank Hold Feature was added. This feature will keep the starter engaged, once the ignition switch is turned to the START position without having to keep the key in the START position.
Exterior
* The front bumper and radiator grille design was changed.
changed
* The rear back door name plate molding was changed
* Running board design was changed
* The roof rack was added as optional equipment
* The rear turn-signal lights was changed from amber to clear
* The roof-rail has been adopted as optional equipment.
* 275/65R17 tires with 17x8JJ-60 wheels are provided as standard equipment.
* 275/60R18 tires with 18x8JJ-60 wheels are provided as optional equipment.
* Wheels were redesigned
Interior
* The center cluster of the dashboard was changed
* The combination meter design was changed
* Added the new steering wheel with controls on the center pad
* The pillar handles and coat hook was changed for the vehicles with side curtain airbags
* The screen of the multi display was changed to a touch screen
* A voice recognition system was added to the GPS system
* Side and curtain shield airbags were adopted as optional equipment
* Drive and passenger airbag system was changed to a dual-stage unit.
* An RSAS (Rear Seat Audio System) was added as standard equipment.
* Power tilt and telescoping features added to the steering column