Usage:
3500 Family Of Engines;
D11N, 776B Tractors;
777B, 785, 789 Trucks
Reference: Service Magazine; December 12, 1988; Page 6; "New Alternator Drive Pulley Has Hardened Wear Sleeve; New Seal Used On Pulley" Service Magazine; September 18, 1989; Page 17; "New Design Alternator Belt Used".
Description of Change: A new alternator drive pulley seal is used on the 3500 Family of Engines. The improved seal works in conjunction with a drive pulley that has a hardened wear surface (sleeve). The new seal reduces wear and oil leakage.
Adaptable To: The new 9X4612 Seal (2) is a direct replacement for the former 6V7196 Seal when used with either the 9Y5286 Pulley Assembly or 9Y7178 Pulley Assembly (1). Former pulleys can not use the new seal. The new seal can only be used with pulleys that have the hardened wear surface (sleeve).
NOTE: The 1W5048, 7C0504 and 7W6824 Alternator Mounting Groups (Illustration 1) may be converted from two V-belts to a single, wide "poly-vee" belt used in the 7E4836 Alternator Mounting Group (Illustration 2). The wide belt has several small V-shaped grooves that fit small grooves in the wider pulleys. The wider belt gives longer service life. The service life of two V-belts can be shortened because of vibration which causes the belts to hit each other.
Illustration 1. 7C0504 Alternator Mounting Group. (1) Pulley. (2) 9X4612 Seal.
Illustration 2. 7E4836 Alternator Mounting Group. (2) 9X4612 Seal.