NP241C Transfer Case Drive Chain, HV-025 4167995

This is the drive chain that lives inside an NP241C transfer case. It wraps the mainshaft drive sprocket and the front output shaft sprocket, and every bit of torque the front axle sees in 4WD runs through it. The part carries OEM number 4167995, commonly cataloged as HV-025, and the same chain is used in the BorgWarner 1370, the NP243 and the NP208.

Chains stretch. On a high-mileage Dodge Ram or GM truck the symptom is a clunk when you shift into four wheel drive, a rattle or slap from under the floor on throttle transitions, and slop in the front driveshaft you can feel by hand with the transfer case in neutral. Once the chain is long enough to ride loose it starts contacting the case, and at that point you are looking at aluminum shavings in the fluid and a housing that may not be worth saving. Replacing the chain during a rebuild is cheap insurance compared to a case.

On the bench: drain the case, split the halves, pull the front output shaft and mainshaft together as an assembly so the chain comes out with both sprockets still in it, then reassemble the same way with the new chain looped over both sprockets before either shaft drops into its bore. Do not try to thread the chain in after the shafts are seated. Reseal the case halves with RTV, not a gasket, and refill with the ATF the transfer case calls for. If you are in this far, replace the bearings and seals at the same time.