6BT5.9 Cummins Crankshaft Adapter 3957841 Parts Catalog Ref No. Part Name Part No. Required 1 Crankshaft Adapter 3957841 1 2 Captive Washer Cap Screw 3968075 6 3 Tuned Vibration Damper 5307831 1 Above is the introduction of the 3957841 Cummins Crankshaft Adapter, while if you need Crankshaft Adapter 3957841, complete Cummins engine or other Cummins product, please further consult …