97 ford f-150 really howls when driving down road

[x1957x]

I have a 1997 ford f-150 4x4 and i checked the lubricants in front end,transfer case, and rear end. The rear end was a quart low but no visable signs of leaking seals or whatever. Tires could be rotated, some inside chopping wear. Not bad though. Is there any ideas on what to check for to see why this howls when driving. Esp. around the 30 mph and up range .. Thanks guys! And girls to!

[Jeremy airjer W]

Is it coming from the front or the rear?

Rotate the tires and see if the noise follows the tires or changes. If it does its tire noise from the cupped tires.

If it doesn't change than try turning aggressively from side to side when it starts making noise. If it changes in intensity than you have a bad wheel bearing. If it still doesn't change its probably in the drive train.

[Scott K]

More then likely it is rear differential whine from the pinion. If it is there on tip in, or on decel, but quiets on hard accel, then it is more then likely pinion whine. You can try to quiet it by either a fluid change with friction modifier, or if the rear fluid has been changed recently, by just adding the modifier to the rear diff. More then likely it will need a rear ring and pinion, and bearings.

[PierBridge]

Wheel bearing?

[x1957x]

Thanks guys for all the help. It was the front wheel bearing on the drivers side. 236.00 for just the bearing. I did the repair my self. Other wise with breaks and a new rotor it is in the 350.00+ range but if thats what it takes. What the heck is a preloaded bearing when they are all sealed? lots of price differance though. Thanks again guys, you have been a great help!!