GEAR-ADAPTER 1543358 - Caterpillar

4.75"
Bore 4 and 6 Cylinder Engines, Including Those Used In Machine ApplicationsThe above engines use two thrust plates which fit around the top of the rear main bearing journal to control crankshaft end play. Each thrust plate has an aluminum bearing surface with a steel back. The plate part number and the words "BLOCK SIDE" are on the steel back side of the plate. During engine assembly, it is very important to install each thrust plate with the steel side against the cylinder block, so the aluminum bearing surface is next to the crankshaft. This will permit the bearing surface to take normal thrust loads from the crankshaft, and give maximum service life.
The correct installation information is given in service manual assembly procedures, but some engines have been found with the thrust plates installed backward. This can cause engine damage. For this reason, it is very important to remember that these plates must be checked for the mark "BLOCK SIDE", and installed correctly during engine assembly. Be sure to follow service manual procedures carefully.