Rear Main Seal

REMOVAL & INSTALLATION

4-Cylinder Engines

1. Remove the transmission and clutch assembly, if so equipped.
2. Matchmark and remove the flywheel or the driveplate and the adapter plate, if so equipped.

   Fig. 1: Rear main seal components — 4-cylinder engines

   Fig. 2: When pushing the oil separator into the case make sure the oil hole is in the bottom position

3. Unbolt and remove the lower bell housing cover from the rear of the engine. Remove the rear plate from the upper portion of the rear of the block.
4. The lower surface of the oil seal casing presses against the oil pan gasket (or seal) at the rear of the pan. On engines with a gasket (2.3L diesel engines), carefully separate the gasket from the bottom of the seal case.

   NOTE: You may want to loosen the oil pan bolts slightly at the rear to make it easier to separate the two surfaces. If the gasket is damaged, the oil pan will have to be removed and the gasket replaced.

5. On vehicles employing sealant around the oil pan, unbolt and remove the pan. Clean the pan and block surfaces of all traces of sealant.
6. Remove the oil seal case bolts, and pull the case straight off the rear of the crankshaft. Remove the case gasket.
7. Remove the seal retainer or oil separator (not all engines use an oil separator) from the case and pry out the seal. Take care not to gouge or damage the metal surrounding the seal. Inspect the sealing surface at the rear of the crankshaft. If a deep groove is worn into the surface, the crankshaft will have to be replaced. Lubricate the sealing surface with clean engine oil.

   To install:

8. Using a seal installer of the correct size, install the new seal into the bore of rear oil seal case. Make certain that the flat side of the seal will face outward when the case is installed on the engine. The inside of the seal must be flush with the inside surface of the seal case.
9. Install the retainer or oil separator over the seal with the small hole located at the bottom. Install a new gasket onto the block surface and install the seal case to the rear of the block. Tighten the bolts to 8 ft. lbs. (11 Nm).
10. Reinstall the oil pan if it was removed, making certain the sealant is correctly applied. If the pan was only loosened, retighten the bolts to the correct torque. If the oil was drained, install the correct amount of motor oil.
11. Install the rear plate and bell housing cover.
12. Observing the matchmarks made earlier, install the flywheel or drive plate.
13. Install the transmission and related components as necessary.

6-Cylinder Engines

1. Remove the transmission and clutch assembly, if so equipped.

   Fig. 3: Use these tools to hold the crankshaft in position while loosening or tightening the flywheel bolts — 3.0L Engines

   Fig. 4: Use this bracket to keep the flywheel from spinning while loosening or tightening the flywheel bolts

   Fig. 5: Cut a little piece out of the seal, so that it can be pried out with a prytool — upon installation, apply engine oil to the sealing lip

   Fig. 6: Use this tool to install the rear oil seal straight and flush in the rear oil seal cover

2. Matchmark and remove the flywheel or driveplate and adapter plate. For the 3.0L engines, use the Mitsubishi tools (MB990767–01 and MIT308239) to hold the crankshaft and flywheel stationary while loosening the flywheel bolts. For the 3.5L engines, use the Mitsubishi tool (MD998781) to hold the flywheel in position.
3. Remove the rear oil seal.
   1. Cut out a portion in the crankshaft oil seal lip.
   2. Cover the tip of a small prytool with a cloth and apply it to the cutout in the oil seal to pry the oil seal out.

      CAUTION
      Take care not to damage the crankshaft and oil seal case.

      To install:

4. Inspect the sealing surface at the rear of the crankshaft. If a deep groove is worn into the surface, the crankshaft will have to be replaced. Coat the sealing lip of the seal with fresh, clean engine oil. Press the new seal into the case with a seal installing tool. The seal must be pressed in square until it bottoms in the case. It is necessary to use the proper tool (MD998718–01) to fit the seal into place.
5. Install the rear plate.
6. Install the transmission mounting plate.
7. Install the flywheel or drive plate and adapter.
8. Install the transmission and related components as necessary.