Description

The Cummins Crankshaft Gear 3901258 is a precision-machined diesel engine timing component designed to transfer rotational motion from the crankshaft to the camshaft and timing system , ensuring accurate valve timing and synchronized engine operation in Cummins diesel engines. This gear is a direct replacement for Cummins OEM part number 3901262 , making it ideal for timing system service, engine rebuilds, and complete overhauls. Manufactured from high-strength, heat-treated alloy steel , the Cummins 3901258 crankshaft gear is engineered to withstand high torsional loads, continuous rotational stress, and heavy-duty operating conditions . The precision-cut gear teeth ensure smooth engagement with mating gears, reduced backlash, and long service life under demanding diesel engine loads. Designed to meet OEM dimensional and hardness specifications , this crankshaft gear helps maintain precise cam-to-crank synchronization, supports smooth valve train operation, and prevents timing drift that can lead to poor performance or internal engine damage. Replacing the crankshaft gear during an overhaul is strongly recommended when wear, tooth damage, or timing inaccuracies are present. This crankshaft gear is commonly used in Cummins diesel engine rebuild, overhaul, and timing system repair applications , including on-highway trucks, industrial engines, and heavy-duty equipment.