From Wikipedia:
The Ford Explorer was released in March 1990 as a 1991 model. It was equipped with a 4.0 L 155 hp (116 kW) V6 engine and 4-speed A4LD automatic transmission or 5-speed M5OD manual transmission. Like the Ford Bronco II it replaced, it was an SUV derivative of the Ford Ranger Pickup, but larger. Following the Chevrolet S-10 Blazer, it came in both 2-door and 4-door bodystyles. It was available with rear or four-wheel drive. The four-wheel drive versions came with a Borg Warner 13-54 part-time four wheel drive transfer case. The 13-54 was available with "Touch Drive" electronic push button shifting as well as manual, lever operated shifting. Both designs were "shift-on-the-fly" designs that allowed the truck to be shifted from two wheel drive to 'four-high' at any speed. All Explorers came with the 8.8" Ford rear axle in either a limited slip or open version with a variety of available gear ratios. Explorers came in 4 trim levels: base XL, XLT, Sport (only available on the two-door version), and the upscale Eddie Bauer Edition. 15 hp (11 kW) was added for 1993 for a total of 170 hp (119 kW). The Limited edition, added for 1993, was available only in the 4-door style and was even more upscale than the Eddie Bauer version. It featured automatic headlights, foglamps, an automatic transmission as standard equipment, an auto-dimming rear view mirror, a center roof console with compass and outside thermometer, special wheels, and a special grille.
Technically similar to the original Ford Explorer, the Explorer Sport came in both rear-wheel drive and four-wheel drive variants. It replaced the 2-door Ford Bronco II, and was larger than the Bronco II. A variant of the Explorer Sport was sold by Mazda as the Navajo, which won Motor Trend's Truck of the Year award but was discontinued in 1994.
Common complaints about the first generation models mostly came from the A4LD automatic transmission. Towing wasn't its strong point and it couldn't handle much more power if the engine saw any aftermarket upgrades. Also, problems came from the automatic locking front hubs. Moderate off road driving would destroy the plastic internals and leave the SUV stuck in 2WD. Manual locking front hubs did not suffer from reliability problems.
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