My truck makes a groaning/whining/humming noise when driving (and no it's not from my passengers). It gets louder when I push the gas pedal, but quiets when I let off. It is also louder when going around a curve, especially when turning right.
Is this normal??
Or is it worn out u-joints, differential, or hub bearing?

 

I dont think its a u-joint because they click and sound like a rock in the tire. It shouldnt be the differential. I'm going with bearing. Jack up each of the front wheels one at a time and grab the tire at the 12 o'clock and 6 o'clock position and see if it moves at all.

 

Power steering pump

 

Does it suddenly go away when you push the brake pedal? If so, I'd say brakes.

 

Thanks for the replies. I'll have to go on a drive soon and test it a bit to see if I can pinpoint it more and maybe find more scenarios.
I have more of an idea what to check for now.
Laramie, I'm not shooting you down, just asking, but how would the power steering pump make that noise? I recently exchanged the fluid, but it did this before then.

 

If the power steering pump itself was starting to die, it may make odd noises like the ones you described. Not out of the realm of possibility.

 

A power steering pump will make that squealing sound when it's dieing.

 

if it is the ps pump then the increase in noise when you give it gas makes sense because you speed up the pulley on the pump when you increase the engines speed.

 

I was thinking ps pump as well. With it parked and running, pop the hood and see if you can tell where it's coming from. Then have someone turn the wheel and see if you get the same growl from the ps pump.

 

this quietened down my old chevy.

change the PS fluid using a turkey baster. walmart has a real nice one for about 7 or 8 dollars, other places might be cheaper. start with 1 quart of PS fluid. with engine off, suck out as much old fluid as you can from the reservoir and discard it into a bucket. stick the baster way down in the bottom where all the nasty $hit lives. you'll get about 1/2 qt. refill and take it for a drive, or crank it up and turn it lock to lock several times. repeat the whole process at least once. see if it helps.

this works for brake fluid removal also.