What causes a whining front-end noise on a Ram 3500 diesel under load?

[GregoryNM]

I’ve been running a 2019 Ram 3500 with the high-output Cummins for a few years now, and lately I’ve been noticing a faint, intermittent whining noise that seems to come from the front end when I’m under a heavy load. It’s not the power steering pump, and the serpentine belt looks fine. I’m just wondering if anyone else has tracked down a similar sound on their heavy-duty diesel, especially when the engine is really working hard.

[Ronald61]

I had a similar faint noise when I was pulling a heavy load. I checked the belt and the tensioner and found the tensioner pulley was kind of stiff. Replacing the tensioner and the belt cut the noise a lot, though I still heard something a bit when the engine worked hard.

[MilaG]

I tried listening with a mechanic stethoscope and it sounded like it was coming from the front of the engine area near the alternator and water pump. I did not replace the water pump yet. The noise would come and go with RPM and load.

[William_R]

Do you think it could be something in the front axle or the drive shaft that only shows up under heavy torque?

[RobertUS]

I kept my eye on it for a while and then forgot about it for a season. It might have been temperature related or just a loose thing that settled after heat cycles.