Mitsubishi built Japan's first 4x4 vehicle, a four-door phaeton code-named PX33, on commission by the Imperial Army back in 1937. Four prototypes were built, but the vehicle did not go into series production. In 1952, the automotive division of Mitsubishi Heavy Industries entered a licensing agreement with Willys- Overland to produce Jeep vehicles. Mitsubishi Motor Corp. continued with Jeep (the original agreement allowed the use of the Jeep nameplate, while its ownership changed from Willys to AMC and Chrysler) production until 1998. In the meantime, Mitsubishi launched a 4x4 series of its own design, the Pajero/Montero in 1982. The second-generation Pajero was introduced in 1991 and continued to September 1999, when it was replaced by a new model range.
The third-generation Pajero justifies and deserves the adjective "new"—and very nearly the adverb "all"—in the original meaning, not in a usual marketing connotation. The SUV is offered in two body styles and sizes and in three- and lytic converter. The engine meets Japan's 2000 TLEV standards. It is rated at 164 kW (220 hp) at 5500 rpm and 348 N•m (257 lb•ft) at 3750 rpm on a 10.4:1 compression ratio, and requires premium grade unleaded gasoline.
The 4M41 DI diesel is an enlarged version of the previous 2.8-L unit, obtaining a 3496-cm3 displacement with 93.0-mm (3.66-in) bore and 85.5-mm (3.37-in) stroke. Chain-driven dual overhead camshafts operate four vertical valves per cylinder via finger-type followers with roller cam contacts. The timing chain sprocket is driven by a crankshaft geartrain, which also drives twin contra-rotating balance shafts. The combustion chamber is a deep bowl in the piston, and the fuel-injection system employs an electronically controlled fuel-injection pump and centrally positioned injectors but is not the common-rail variety. Unique for this engine is a cooler for the EGR (exhaust gas recirculation) system. The finned watercooled heat exchanger is placed between the exhaust manifold. The EGR valve cools exhaust gas from 300 to 150°C (570 to 300°F) before admitting it to the induction system to increase filling efficiency and reduce NOx and smoke emissions. The 4M41 diesel is rated at 130 kW (175 hp) at 3800 rpm and 382 N•m (282 lb•ft) at 2000 rpm.
The Pajero's propeller shaft is made of carbon-fiber-reinforced plastic.
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The Pajero's transmission choices in the Japanese market are all automatics, reflecting the country's overwhelming preference for this type of transmission. For export, Mitsubishi offers manual transmissions. All automatics are electronically controlled, adaptive INVECS-II, in four- and five-speed versions. The Sports-Shift unit, again both in four- and five-speed specifications, allow manual selection of gears by moving the lever in the parallel +/- gate. The planetary gear-type center differential with viscous-coupling-type differential limiter provides variable torque split, ranging from the normal 33/67 ratio to a 50/50 ratio between the front and rear wheels. The transfer case has all-wheel-drive 2H and 4H for road and slippery surface use and directly coupled 4HLc and 4LLc for off-road, snow, and steep-hill operation. A hybrid rear limited-slip differential is available, combining a helical-gear LSD and a viscous-coupling-type LSD within the unit.
Pajero's independent suspension has "double wishbone" unequal-length upper and lower arms.
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Another unique feature is a carbon-fiber-reinforced plastic propeller-shaft tube. The tube is composed of the main helically wound tube and an end hoop layer. The steel shaft is fitted to the CFRP tube and; in case of a severe frontal impact, the steel shaft's trigger flange contacts the hoop layer, and at a preset load the hoop layer and the helical body instantaneously separate. The hoop layer wedges into the helical tube, contracting the tube and providing an ample energy absorbing length.
Jack Yamaguchi
