LAMP 5W4970 - Caterpillar

The roller-type lifter used in the 3400 Family of engines. The roller pin locating wire only locates the roller pin in the lifter body. The wire does NOT retain the pin in the body. A loose locating wire might indicate a loose pin, but will not cause a loose pin.7. Damage to the descending slope of the cam lobe(s). This is caused by the downward impact of the lifter roller after the valve train and lifter had instantaneously separated from the lobe near the top of the lobe.8. Damage to valve faces caused by the impact of very rapid closing.9. Damage to the upper halves of the crankshaft main bearings. (Only the upper half of the bearing has the lubrication groove and this reduces the amounts of loads that the upper half can handle.) On the 3406 and 3408 Engines, check especially the front and rear mains. Check the front, rear, and center mains on the 3412 Engines.
Engines equipped with a sliding gate or flapper exhaust brake will be damaged at a lower amount of overspeeding when the exhaust brake is used. This is caused by excessive back pressure against the exhaust valves.