Written By, Mike McGlothlin
CAT 3406
History
You would be hard-pressed to find a more universally recognized engine in Caterpillar’s lineup than the CAT 3406 engine. The heavy-duty, cast-iron inline-six is perhaps best remembered for its use in North American Class 8 trucks, but it was also called upon for use across the globe. First introduced in the 1970s, the foundation of CAT 3406 history began with direct injection and standard turbocharging, while its 5.40-inch bore and 6.50-inch stroke brought total displacement to 893 cubic inches (14.6L). Offered in A, B, C, and E models (3406A, 3406B, etc.), each being more technologically advanced than the other, the 3406 enjoyed a 35-year production run.
Common Applications
In addition to being offered in Class 8 tractors, the CAT 3406 can be found in heavy-duty vocational trucks and even motorhomes. However, it’s also a major player in the off-highway segment. In agriculture, the 3406 was a hit in heavy tillage farm tractors. In construction and earth-moving equipment, it was a popular choice in dozers, motor graders, and wheel loaders. For industrial applications, the 3406 was a regular in stationary gen-sets, oilfield generators and pumps, drilling and mining equipment. Finally, it was a mainstay engine in the marine sector, often powering tugs and push boats, commercial fishing boats, yachts and ferries, and pilot and patrol vessels, applications that showcased the durability reflected in published CAT 3406 specs.
Production Run
Manufactured from 1973 to 2007, the 3406 engine’s production run began with the 3406A (1973-1987), transitioned to the 3406B (1987-1993), then the 3406C (1993-1998) and 3406E (1993-2007). By far, the most popular version was the electronically controlled 3406E, which technically began production in November of 1991 and that had the capability of transforming a Class 8 semitruck into a 600-plus hp hot-rod with a few simple ECM tweaks. In 1999, CAT built and shipped two final on-highway 3406E’s from the factory—the last pair in a line of best-selling truck engines with a worldwide population that nearly reached 575,000.
How It’s Remembered
All CAT 3406 models are renowned as powerful, durable workhorses in every industry they serve. Whether it’s a 310hp 3406A model or an 800hp version of the 3406E in a marine vessel, it’s an engine that was reliable and dependable in any condition and in any configuration. As a result, CAT’s 3406 still lives on today—especially the 3406E in Class 8 trucks, where it’s become legendary. Just as Cummins’ 855 Big Cam was the king of OTR trucks in the 1980s, the 3406E was the king of the road in the mid 1990s to mid 2000s. Even though the 3406 was phased out in the late 1990s, its overall design formed the basis for the C-15 that replaced it.
Sources:
Big Bear Engine Company
https://www.4btengines.com/cat-3406-engine/
Final Units Built
https://www.cat.com/en_US/blog/history-of-cat-trucking.html
Model Years And Power Ratings:
CAT 3406E Model Years/Engine Prefixes
https://repair.diesellaptops.com/caterpillar-truck-engine-explained/
