Usage:
3406 And 3408 Truck Engines
Description of Change: A new bearing is used in the 4N4406 Nose Housing Assembly in the air starting motor groups on 3406 and 3408 Truck Engines. The new bearing is a "needle bearing" design and will have a longer service life.
Formerly, a bronze bushing was used.
Adaptable As: The new 6D3787 Bearing is currently used in the 4N4406 Nose Housing Assembly. Formerly, the 4N4407 Bushing was used in the 4N4406 Housing Assembly. The 4N4406 Housing Assembly is a direct replacement for the earlier housing with the former bushing. Because of a difference in the outside diameter the new bearing is not a direct replacement for the former bushing.
To use the new bearing in earlier housings, the existing bearing bore must be machined to a diameter of 25.400 ±.013 mm (1.0000 ± .0005").