Usage:
769C Trucks ( 1X2877-Up ),
768C Tractors ( 2X350-Up)
To test 3408 Engines (48W17688-Up) used in the above machines, the vibration damper must be removed. These engines use a new crankshaft that has thicker webs between the outer main journals and the outer rod journals. These engines also use a lower interia flywheel.
If these engines are tested out of chassis on a dynamometer, the rubber in the vibration damper can fail. This happens because of torsional vibrations from the engine and dynamometer. There is no torsional vibration problem when the engine is run in the chassis.
When the engine is run out of chassis without a vibration damper, the lug speed during tests should not be less than 1500 rpm. Be sure to reinstall the vibration damper after the out-of-chassis testing is completed.