97 Roaring sound

Hello All,

I have a 1997 Bravada that just started making a loud fan like roaring sound. The faster I go the louder it gets. I start hearing it around 30 mph and it is really noticable by 50 mph. I have put it Neurtal and let it coast and the sound is the same so I think I can rule out the engine. I also found a parking lot and cut the wheel one and went in a circle and then the other way and in both cases could not hear the sound at all. No clicking or anything like you normally hear from a CV Joint. I will say it is constant and only gets louder when I go faster. Going a round a corner or braking changes nothing.

I also want to point out I have replaced all of the rotors and calpiers for other reason so they all are new. I also opened the fill plug for the front diff and it is full. The transfer case seems to be full as well. I did notice that case the half shaft (I think it called) is rusty and seems like maybe water could get in it. Is there any bearing in there that could be going out? I am talking about the one on the right side of the front diff that is in-between the diff and CV Joint.

One other thing that might be important is this occured after a pulled about 5000 pounds behind it for about 60 miles. I was very gental on the gas and it was mostly highway too. I also don't see anything funny with the tires.

Any ideas? Sorry about the book by the way.

Wheel bearing maybe?

I thought about a wheel bearing as well but I have had them go bad it doesn't sound the same as one. My wife took into a mechanic today and they said they don't think it is a wheel bearing either but do think it is a bearing some where in the front end. They even had it on a lift and in gear listening to it with a stethoscope and could not figure it out for sure. Their sugesstion is to let it go till it gets worse and can be pin pointed. I am just trying to figure it out before it gets to be a big deal.

Mine had a roaring noise that would get slightly louder when I veered to the right and slightly quieter when I veered to the left at 50 mph. It turned out to be a worn out passenger side front hub.

Thanks for the replys guys. I guess time will tell for now mine. The only thing I have noted different yet is going up a steep hill makes it get a little louder. At this point I think I will just drive until A it gets worse or B hopefully it doesn't get worse and I can just forget about it. Some how I don't think B will happen. I will update more as it changes. It is not a daily driver. I only drive it when it snows or when I need to haul or pull my trailer.

You can remove the front driveshaft and do a short test drive on level ground to see if it is the front driveshaft/transfercase.
I had a vibration due to a bad u-joint on the rear driveshaft of a truck I had.

It could just be fan noise. GM's use silicon oil based fan clutches that default to always on when they fail, to protect the engine. Check out this thread for more info: http://www.justanswer.com/questions/1aagq-check-fan-cluch-1997-chevy

Good points on the drive shaft and fan. I will check the fan out. One question though that came to mind about the fan is when I am going down the road and if I go in neurtal and let it coast as the engine RPM comes down shouldn't the fan sound change as well since it is drove off of the engine or am I wrong about how it works?

One other thing about the fan I have noticed that when the engine is cold and I start off down the road I do hear it get loud about until it shifts into second then the sound goes down which I assume is normal?

Had roaring in my 98...changed both front hubs and quieted down some.then changed rear u-joints..no change..changed front u-joint. Cured problem ..hope this helps