Balance Shaft: Operation
WARNING: This page is about a different car, the 2005 Jeep Liberty. However, it is still accessible from the selected car via links, so may be relevant.
The balance shaft assembly includes four balancers on two shafts. The balance shafts are connected by helical gears, and the assembly is timed with the engine. The dual-counter rotating shafts rotate at twice the engine speed and decrease second order vertical shaking forces caused by component movement. Balance shaft oiling is provided through oil passages in the crankshaft carriers.