The document provides instructions for removing and installing the flywheel housing on a Caterpillar C4.2 engine. The summary is:
1) To remove the flywheel housing, first remove the electric starting motor and flywheel. Then use lifting tools to remove the housing bolts and housing.
2) To install the flywheel housing, first install a new oil seal and check the dowels. Clean the mating surfaces and install a new gasket on the cylinder block. Place the housing in position and install the bolts to secure it.
3) The document also provides instructions for removing the flywheel, crankshaft rear seal, and installing the rear seal.