3408 Truck Engines
Description of Change: A larger plug is now used in the ends of the rocker arm shaft assembly for 3408 Truck Engines.
A different bar stock, which has a larger inside diameter, is used to make the rocker arm shafts. Because of the larger inside diameter of the tube stock, the diameter of the counterbore in the shaft was increased. The larger diameter counterbore makes a larger plug necessary.
Adaptable To: The L1022 Plug can be installed in the rocker arm shafts with the larger, 16.66± 0.03 mm (.656± .001 ") diameter counterbores. The 5B1866 Plug is still available for use in rocker arm shafts that have 15.98± 0.03 mm (.629 ±.001 ") diameter counterbores.
Location of the L1022 or 5B1866 Plug in the ends of the rocker arm shaft assembly.