Whining noise during acceleration

[Tapout417]

Ok I have a 2001 Denali AWD 6.0, and when I accelerate it makes a whining noise as if it were low on power steering fluid, well I just replaced the power steering pump today and the ring and pinion with bearings about 1000 miles ago. Still whining, the shop today said it could be transferred case but I doubt that because I had it inspected when the ring and pinion was replaced. Any info is greatly aprreciated

[gmtech1]

Is the noise RPM related or vehicle speed related. Drive the vehicle to speed that whine starts, shift into neutral and rev the eng, if the noise changes then it's not in the drive line.

[Tapout417]

I just took it out, it is defiantly RPM related. I can rev it in my garage and hear it, so I took it for a drive the noise starts right when I accelerate, so I shifted into neutral and reved it up and the whine got alot louder

[FishFind]

Take off your belt and run it in your garage again and see if it stops. If so you will have to see what pully is doing it.

[Tapout417]

Ok I'll have to try that this weekend I'm outta town till then, how will I be able to identify the pulley?

[gmtech1]

The easiest way I found is to use a stethascope. You can get one from a parts store. REmove the end on the tube and just use the tube. Move the tube from pully to pully until you find the noisy one.

[Tapout417]

Gmtech1 is that with the belt off or is it possible to do it with the belt on?

[gmtech1]

With the belt on, run eng till you hear the noise, then move the hose around each pulley, and componants like the alternator and p/s pump and water pump and see where the noise is loudest.

[Tapout417]

Ok sounds good I'll give it a shot tomorrow, thanks

[Tapout417]

Ok tried the stethascope and no luck, I couldn't pin point a significant noise that was different from any where else, any other suggestions?

[gmtech1]

FishFind suggested to remove the belt and see if the noise was still there, is it?

[Tapout417]

That hasn't been a option to try im currently outta town with the truck but I'll have it home this weekend and give that a try, just didn't have the tools to remove the belt in the hotel parking lot

[bcopeland]

Is it coming from under the hood or from the rear of the vehicle? I had similar problems on my 2001 and it was the rear expansion value.

[Tapout417]

Its coming from under the hood, I just had another power steering pump put on and completely flushed bc that what the shop said, and it still whining, 3rd new pump since January and no fix, noise driving me crazy and not one mechanic can figure it out, I've told them unless the guarantee the noise will be gone once they replace something don't work on, and so no one will

[pthomas8]

I have a 2005 Denali making the same whining noise but when I tried the acceleration and neutral test the sound went away. I believe this may eliminate the drive train as the source. However, what does this reduce my choices to?