Nissan NV 3500 HD Loud Revving Sound

Has anyone else noticed that their Nissan NV 3500 HD passenger van makes a really loud revving or fan-based noise when they accelerate?

I used to be a truck driver. I was surprised when my NV started making a loud revving sound when I accelerate. It sounds as if the main cooling fan goes into overdrive. I would compare it to the noise level of a larger, turbo-charged diesel engine.

Apparently the problem is intermittent, meaning it doesn't happen all the time. The Nissan tech was able to hear it once, but when we restarted the engine the noise went away. The tech mentioned that the fan is driven by an electronic clutch, controlled by the system computer. Built-in sensors send the computer feedback, and the computer decides when the fan needs to kick into high gear. Something in that chain of command isn't quite working.

The problem seems to come back for a day or maybe two at a time, and may not surface again for several days or a week.

I'm curious to know if anyone else has had this problem, and if so, how you fixed it?

-Cheers.