Usage:
3406B Truck Engines
Description of Change: Effective with 3406B Truck Engines 4MG3600-Up, several new parts are used in the timing advance mechanism in the fuel pump and governor drive group. On these engines, there is a possibility that the locknut on the end of the adjustment screw can be stripped due to lack of thread engagement and difficult accessibility. See illustration. This locknut has been replaced by a new, thicker nut, which reduces the possibility of stripping the threads when the nut is tightened.
Location of the wider locknut in the timing advance mechanism.
Adaptable To: The new 8L5832 Nut can be installed as a direct replacement for the former 4B2049 Nut. In addition to the serial numbers, truck engines with the new timing advance parts can also be identified by the conical shaped cover over the end of the advance mechanism. Tighten the new nut to 4.5 N ·m (40 lb in).