isx cm2350 oil pump

[MPDiagnostics]

If it sounds like a silage chopper to you, chances are this sound may be even coming from the High Pressure Fuel Pump. If you had the fuel pump removed recently for any reason, Cummins does mention that if you don't "time" the fuel pump it may result in a "chopper/helicopter" type sound.

The first question you should answer is how many miles on that fuel pump? If its 400k on it you need to replace the fuel pump internals as personal insurance.

My friend has shown me a fuel pump that actually had a bent crankshaft which made a horrible noise.

Wouldn't hurt for you to pull the fuel pump head and inspect/replace internals.

Rawze has videos on this as well as many posts on this forum.

This is a good place to start.