Cummins 3929028 Genuine Camshaft Gear (1989-2000 5.9L Cummins)

Fitment

Our listing covers the 1989-2000 5.9L Cummins. In pickup terms, that is two generations of Dodge Ram and three fuel-system setups:

• 1989-1993 Dodge Ram D250/D350 and Power Ram W250/W350 with the 5.9L 12-valve and Bosch VE pump
• 1994-1998 Dodge Ram 2500/3500 with the 5.9L 12-valve and Bosch P7100 pump
• 1998.5-2000 Dodge Ram 2500/3500 with the 5.9L 24-valve and Bosch VP44 pump

A 1998 Ram can be either a 12-valve or a 24-valve. The inline P7100 pump with a shutoff solenoid on top means 12-valve; the VP44 rotary pump means 24-valve. Verify fitment by VIN, or call the shop and we will check it for you.

Why this part

On the 5.9L, the camshaft and the injection pump are both gear-driven from the front of the block, and the cam gear sits in that gear train. The best-known threat to it is the killer dowel pin. That steel dowel locates the front gear housing on the block, and heat cycles and vibration can work it out of its bore and drop it into the timing gears. If it falls into the oil pan, no harm done. If it wedges between the cam gear and the injection pump gear, it can crack the cam gear, the cam nose or the gear housing, and the worst case is an engine that cannot be repaired.

The 1994-1998 P7100 trucks are the highest-risk years, because the heavier pump adds vibration to the gear case. The 1989-1993 VE trucks are in the affected range too, and some 1999 24-valve trucks have had it.

If you are replacing a cam gear, the gear cover is already off, and that is the time to deal with the cause. A KDP tab is held by the neighboring gear-cover bolt with red thread locker at 18 ft-lb, and it physically keeps the dowel from backing out. Replace the front crankshaft seal while the cover is off, and let the RTV on the cover cure 24 hours before you start the engine.

What you get

• One Genuine Cummins camshaft gear, part number 3929028
• Gear only: gaskets, seals and KDP hardware are not listed with it

About Cummins

Cummins started in Columbus, Indiana, in 1919 and still has its headquarters there, with more than a hundred years of building diesel engines behind it. To a pickup owner, Cummins means the inline-six in heavy-duty Dodge and Ram trucks: the 5.9L from 1989 to 2007 and the 6.7L from 2007.5 forward. This gear is the factory Cummins part, not an aftermarket copy. See more Genuine Cummins parts.

Frequently asked questions

Does this gear fit both the 12-valve and the 24-valve?

Our listing covers the 1989-2000 5.9L, which takes in the 12-valve through 1998 and the 24-valve from 1998.5 through 2000. Because a 1998 truck can have either engine, verify fitment by VIN or call us before you order.

Should I put in a KDP tab while the gear cover is off?

Yes. The killer dowel pin is one of the ways these cam gears get cracked in the first place. The tab is a small part, the cover is already off, and Diesel Hub recommends installing one on every 12-valve rather than waiting for a problem.

How should I turn the engine over during gear work on a 12-valve?

Never rotate the engine with the timing pin engaged; it will break off in the front cover. Turn the engine with a barring tool such as the OTC 7471A, or with a 22 mm socket on the alternator nut.

Questions on fitment? Call the shop at the number in the header. We install everything we sell.