When my truck is warm I hear a loud fan type noise. I really notice it when I am pulling my 10K pound camper with the AC on and if the temp is above 90 outside. When I slow down and down shift you can really hear a whirling noise like the fan is spinning really fast. When I come to a stop or when it cools down I don't hear it anymore. You can almost hear is stop right away.

Could this be the fan clutch? If so, how do you check to see if the fan clutch is bad?

Any help would be great

 

clutch is acting normally....when engine is cold fan should spin freely with little resistence....thats it.

 

Mine sound like a wind tunnel when it kicks in, sucking in birds, rocks and small children!!!

 

Once mine kicks in, it has the same affect as Dodge359's fan...mine will even start to pull in some little cars

 

That actually means your fan clutch is good. However, if it runs excessively it could mean you need to clean your radiator. The crankcase vent system wasn't thought out too well on these trucks.

 

First time I heard mine thought a Cessna was trying to land behind me.