Mitsubishi Pick-ups and Montero 1983-1995 Repair Guide

Identification

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See Figures 1 through 8

On most models, the Vehicle Information Code Plate mounted on the firewall in the engine compartment holds the information as to which transmission the vehicle is equipped with. On the third line, labeled "Transmission", model is listed followed by a space, then either the axle ratio or the serial number is stamped following the space.



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Fig. Fig. 1: The transmission identification tag is located on the left side of the transmission-MA 904A, AW 372 and KM 148 transmissions



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Fig. Fig. 2: The AW 372 transmission identification tag breaks down into 5 categories of numbers



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Fig. Fig. 3: All of the Mitsubishi trucks and Monteros utilize the same type converter

There are five different possible automatic transmissions available for the Pick-ups and Monteros from 1983-95. The transmissions are the MA 904A, the AW 372, the KM148 (4WD), the R4AC1 and the V4AW2 or 3 (4WD). The MA 904A is the oldest transmission available, and was stock on the 1983-86 Monteros and Pick-ups. This transmission is actually a Chrysler Torqueflite transmission. The MA 904A transmission combines a torque converter and a fully automatic 3-speed gear system. The converter housing and transmission case are an integral aluminum alloy die casting. The transmission consists of two multiple disc clutches, an overrunning clutch, two servos and bands, and two planetary gear sets to provide three forward ratios and a reverse ratio. The common sun gear of the planetary gear sets is connected to the front clutch by a driving shell which is splined tot he sun gear and to the front clutch retainer. The hydraulic system consists of an oil pump, and a single valve body which contains all of the valves except the governor valve.

The AW 372, KM148 (4WD), R4AC1 and V4AW2 (and V4AW3) (4WD) are 4-speed units, consisting of a gear type oil pump, 3 multiple disc clutches, 3 one-way clutches, 4 multiple disc brakes and 2 planetary gear sets to provide 4 forward ratios and a reverse ratio. Fourth gear is a 0.668:1 overdrive range. The hydraulic control system provides fully automatic operation based on vehicle speed and throttle opening.

The KM148 and the V4AW2 (and V4AW3) incorporate a constant mesh type transfer case for use in 4WD vehicles. The transfer case has a high/low and a 2WD/4WD position. By operating the transfer control lever, running at 2WD high (2H), 4WD high (4H) or 4WD low (4L) can be selected freely. The KM148 transmission is the same as the AW372 from the governor assembly forward, and the V4AW2 (and V4AW3) is the same as the R4AC1 from the governor assembly forward.



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Fig. Fig. 4: Internal schematic of the MA 904A automatic transmission components-1983-86 Pick-ups and Monteros



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Fig. Fig. 5: Internal schematic of the AW372 automatic transmission components-1987-89 Pick-ups



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Fig. Fig. 6: Internal schematic of the KM 148 (4WD) automatic transmission components-1987-89 Pick-ups and Monteros



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Fig. Fig. 7: Internal schematic of the R4AC1 automatic transmission components-1990-95 Pick-ups



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Fig. Fig. 8: Internal schematic of the V4AW2 (and V4AW3) automatic transmission components-1990-95 Monteros

Transmission part and identification numbers for the MA 904A, the AW372, and the KM148 are stamped on the left side of the case just above the oil pan gasket surface. The 1st 2 numbers are the manufacturing year. The 3rd number is the manufacturing month with "A" meaning January and "M" meaning December. The 4th number is the transmission classification. The 5th number is a check digit and the last set of numbers is the serial number.

The transmission identification numbers for the R4AC1 and the V4AW2 (and V4AW3) are stamped on the vehicle information plate located on the firewall in the engine compartment. The 1st 5 numbers indicate the transmission model. The last 4 numbers indicate the final gear ratio.

The recommended and preferred fluid is Mopar ATF Plus Type 7176 or Dexron® II (or its preceding fluid) automatic transmission fluid.

All of the automatic transmissions utilize a torque converter that consists of an impeller turbine stator, a oneway clutch and front and rear covers. It is a non-serviceable, sealed constructed unit, in which the surfaces of the outer and inner covers are welded together.

Torque convertors are coded by the manufacturer and sold through varied parts networks. Specific part numbers are used to identify the convertors and to allow proper alignment to the transmission. When replacing a converter, verify the replacement unit is the same as the unit originally used with the engine/transmission combination.

 
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