Usage:
3406 Truck Engines (Equipped With A BrakeSaver)
In some earlier BrakeSavers used with 3406 Truck Engines, the ring gear assembly was fastened to the rotor assembly with four 3/8" bolts that were an equal (the same) distance apart. These bolts are used for assistance in disassembly and assembly of the unit and also for shipment.
The load for the BrakeSaver is carried through twelve 5/8" bolts that install through the flywheel, rotor plate assembly, and into the crankshaft.
In later BrakeSavers, the bolt hole locations in the ring gear plate assembly and the rotor assembly changed. One of the bolt holes in each part is moved 30° on the same bolt circle as shown in Illustration 1.
Illustration 1. Location of earlier and later mounting bolt holes.
Illustration 2. Modification to later 9N3284 Ring Gear Plate Assembly.
If the ring gear plate assembly needs replacement on earlier engines, one of the four bolt holes will not be in alignment. On these engines it is permissible to install only three bolts instead of four. Three bolts have enough strength to hold the unit together.