Usage:
3406 Direct Injection Truck Engines
Description of Change: 3406 Direct Injection Truck Engines now have a new wider crankshaft gear. The new gear will give improved service life.
The new crankshaft gear has teeth with a different shape than the teeth on the former gear. A new idler gear is also used, to engage with the crankshaft gear. The crankshaft did not change.
Adaptable To: The new 2W442 Idler Gear Assembly is a direct replacement for the former 7N6678 Idler Gear Assembly, which is canceled. The new 1W9302 Crankshaft Gear and the new 2W442 Idler Gear Assembly are direct replacements for the former two 7N7591 Crankshaft Gears and 6N1950 Spacer, and former 7N6678 Idler Gear Assembly.
New 1W9302 Idler Gear.
The new 2W440 Crankshaft Assembly (crankshaft and gear), when used with the new 2W442 Idler Gear Assembly, is a direct replacement for the former 6N3907 Crankshaft Assembly and former 7N6678 Idler Gear Assembly. The new crankshaft gear or crankshaft assembly can not be used with the former idler gear. The new idler gear can be used with the former crankshaft gear and spacer, but this could result in shorter service life for the gears. Caterpillar recommends the new gears be used together.
