Usage:
D348, D349 Off-Highway Truck Engines;
992 Loaders;
772, 776 Tractors;
773, 777 Trucks
Description of Change: Several improved tube assemblies are used in the engine oil line groups for the above models. On all of these models, a new tube assembly is used for the oil supply to the front and rear idler gear bearings. See Illustration 1. The new tube assemblies are stronger than the former tube assemblies.
Illustration 1. Oil supply tube for idler gear bearing.
The same type of change to a stronger tube assembly was made to the vent line on all of the models except the 772 and 776 Tractors and the 773 and 777 Trucks.
On all models except the 772 Tractors and 773 Trucks, the oil filter inlet and outlet tube assemblies are changed. The 772 Tractors and 773 Trucks have a different type of oil filter inlet and outlet. As shown in Illustration 2, the former tube assemblies were made as one piece. The weight of the former tube assemblies and engine vibration caused a side force on the top of the tube assemblies. In some engines, this caused scuffing (surface wear) in the bores of the oil filter base. As shown in Illustration 3, an elbow and a straight tube assembly are used for both the oil filter inlet and outlet. This design prevents any side force on the top of the tube and scuffing in the bores of the oil filter base.
Also, the new tube assemblies for the oil filter inlet and outlet have o-ring grooves that are made by forming (process that bends) the end of the tubes. The former tube assemblies had connections with grooves for the o-rings. These connections were welded to the tube. Some of the former tube assemblies had cracked or leaked at the weld junction. The new tube assemblies will prevent this type of problem. The same type of change is made to the oil drain tube assemblies for the turbocharger on the 992 Loaders, 772 Tractors and 773 Trucks and to the oil filter bypass tube assemblies for the 772 Tractors, 773 Trucks and D348 Off-Highway Truck Engines with remote oil filter group.
Illustration 2. Former oil vent tube and oil filter inlet and outlet tubes for D348 Off-Highway Truck Engine.
Illustration 3. New inlet and outlet lines for oil filter.
Adaptable As: Direct replacement when the necessary parts are used together. See the parts charts.
