TRANSMISSION AR 3154721 - Caterpillar

Caterpillar Engines Equipped With An Air Starting MotorDescription of Change: A new bearing is used in the 4N4406 Nose Housing Assembly in the air starting motor groups on Caterpillar 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").