Questions on our 3406B/C Governor Group – Truck Engine Rebuild Kit

We’re getting lots of inquiries about our 3406B and 3406C governor group rebuild kit for truck engines.  Because of that, we decided to do a quick post about the most important elements of this complete kit of 100% Cat OEM parts.

This rebuild can solve certain early problems and sometimes forestall more involved fixes.

People are happy to learn that the kit is an actual upgrade and not a basic parts-for-parts replacement kit.  The upgrade results in longer service life,  prevention of certain catastrophic  governor failures, and improved performance.  

To start, it’s updated with the very latest style flyweight carrier, the latest style flyweights, and latest governor races. 

As many of you know, the races and flyweight arms typically wear down the fastest.   This upgrade improves longevity of those components because the surface areas are larger than previous versions. 

In addition to slowing wear rates considerably, the new carriers are designed to minimize catastrophic failure.  That’s because the updated carrier possesses stops which prevent a worn flyweight from damaging your governor housing.   Please see the first image of a housing destroyed by this problem in old-style carriers.

We also pre-assemble a key component that cause many people confusion and is often assembled incorrectly.  But we have to first point out that the most important part in this assembly is the bearing in the second image.

Notice the important difference between the after-market bearing on the left and the CAT OEM bearing on the right.  The shoulder on the inner race of the right CAT bearing is critical.    It allows the bearing to absorb thrust far more effectively than many after-market bearings as most aftermarket bearings do not have this feature.

Next is the picture of that bearing mounted by us in-house.  We install all seven parts in that assembly which many of you will know as the “tach shaft.”

Finally, the kit also includes an upgraded Governor Spring.   The new spring improves throttle response and raise your rack-setpoint/high idle to govern your engine at approximately 2100 RPM under full load (high idle with no load will be higher than 2100 rpm, this is normal).

Finally,  the last three images are the 65 total parts included in the kit.  Below is the link to the governor kit in our store which lists all parts in the kit along with other information.  After that is a link to this same article on our blog.

Please let us know if you have more questions.

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