Good Morning, I drive an 01 Ram 3500 Cummings with a 6 speed. Upon hard acceleration uphill or simply merging into traffic, there’s a whistling noise coming from the engine compartment. It’s faint at best and sounds like it’s coming from the passenger side. I’ve checked all innercooler boots and clamps, the turbo to innercooler clamp, replaced both graphite gaskets at the grid heater and even replaced the cap on the fuel filter housing. I’ve also verified that the small vacuum lines and rubber connections are in good shape. I’m the original owner and have done nothing in the way of adding performance upgrades. (Tuner, fancy exhaust, fancy air cleaner....etc) This truck has been well maintained using only OEM parts when needed. As a result of making sure the oil, air and fuel are always clean, I just turned 450,000 miles. That said, something is now causing this whistling noise and it’s got me baffled. The VP44 is the original one. Could I be looking at the possibility of losing an injector pump even though my pressures are within spec? What am I missing? Thank in advance.

No. At idle, there is no noise and accelerating in the driveway makes no noise.

I’ve gone through everything I know sir. I’ll retrace my steps. Maybe I missed something. I’ll start with the innercooler tubes and joints. I would think that would be the only place where pressure builds the most.

You’re right. There is no “g” in it. That’s where proofreading pays off. Apple apparently kicked out Cummins. I will try all of your suggestions. Thanks for your guys for your time.