RING-WEAR 1838443 - Caterpillar

D398B, D399, 3408B, 3412B Industrial, Marine, Generator Set Engines;
3500 Family Of EnginesDescription of Change: A new nut for retaining the impeller on the shaft is used in the fresh water and raw water pumps on the above engines. The stainless steel used to make the new nut is more corrosion resistant than the stainless steel used in the former nut.Adaptable To: The applicable new nut can be used as a direct replacement for the former nut as follows. The former nuts are still serviced for other applications. For D379B, D398B, and D399 Industrial, Marine, and Generator Set Engines using the 7L3222 Sea Water Pump Group, 2N0955 Fresh Water Pump, or the 6L1866 Raw Water Pump Assembly, the new 7X2651 Nut replaces the former 3H2018 Nut. The same change was also made for 3408B Industrial, Marine, and Generator Set Engines equipped with the 3N7714 Sea Water Pump Group.
For the 3408B and 3412B Industrial, Marine, and Generator Set Engines and the 3500 Family of Engines using the 7C3613 Sea Water Pump Group or the 7C3614 Sea Water Pump Group, the new 7X2652 Nut replaces the former 8C0503 Nut.
For the 3500 Family of Engines equipped with the 5N5757 Sea Water Pump Group, the new 7X3148 Nut replaces the former 5N9011 Nut.
In the parts service 1N8351 and 2N2407 Raw Water Pump Groups, the new 7X2650 Nut replaces the former 4M2347 Nut. Also, a new 7X2652 Nut, instead of the 8C0503 Nut, is furnished with the 7C3493 Shaft to replace the former 3N8451 Shaft.