3406 And 3408 Truck Engines
A 1N3246 Retainer is used to hold the spring in the oil pump bypass valve for 3406 and 3408 Truck Engines.
Any time an oil pan is removed from one of these engines, check to make sure a 1N3246 Retainer is used to hold the spring. The part number is on the retainer.
Formerly, a 4N522 Retainer, which is now canceled, was used. It was possible for the 4N522 Retainer to break. A broken retainer will cause the oil pump bypass valve to open and it will not close. With the bypass valve open, not enough oil will flow through the engine to give good lubrication.