need opinions

[Schicken bone]

posted earlier on howling noise but no response. checked shaft on turbo. does have movement. but truck coasts to 20mph with clutch pedal depressed and transmission out of gear, still have howling. could this still be the turbo?

 

[Alan Reagan]

With the clutch depressed and coasting, it wouldn't be the turbo. There is no load on it at idle.

 

[LMarshall]

Have the same noise. Can't get any help here.

 

[p-Bar]

Rear end diff???

 

[Nightram]

Sounds dumb, but are your tires choppy?

 

[mberry]

Could be either agressive tread on the tires or it's time to change the gear oil in the diffs. How many miles are on it? Have you ever changed the gear oil?

 

[LMarshall]

I can't pinpoint where the noise is coming from. The tires are summer tread and are fine.

It has 21,000 miles and I haven't changed the gear oil. I have it to put in but haven't gotten to it. It's the same noise I'm reading about that other guys have been having trouble with. Whining, howling noise between 20 and 30. Much worse when cold. The colder the louder the noise. It happens under acceleration or in neutral coasting down hill. It's all speed related. Some feel it's the driveline bearing or carrier bearing.

 

[mdepot]

Ok, this probably isn't it, but some 3rd gen trucks get a howling noise in the cab from wind noise leaking through the doors. It's usually worse when the heating system fan is on high. Next time you hear it open a window a couple of inches and see if the noise goes away. I'd laugh if that's is all it is.