I have a 99 Silverado with a 5.3. It has 63,000 miles on it. I bought it used with 47,000. It has developed a whining noise that seems to get louder when you give it more throttle. It is worse in 3rd gear than in overdrive. If you leave off the throttle while going downhill, it virtually disappears. I have been reading some posts about the fuel filter needing changed. I will try that. However, when I turn the key on and listen, I can't hear the fuel pump running/whining. Does this still sound like a fuel pump problem?

I may be going in a completely opposite direction of what is going on, but I will through my 2cents in anyway.
My experience with fuels pumps is that if the vehicle starts, the pump is good....

Does the whining continue when you let off the gas and just gradually goes away, or is it instant? If it is gradual (I have know idea how to spell that word) you might have a sloppy rear end. Where the gears aren't as tight as they used to be. Another way to maybe confirm this would be to listen for a clunck sound when you shift from park to drive/reverse or from drive to reverse.

Like I said though this may not be the problem at all. I just had a vehicle that had a problem similar to yours and a sloppy rear end was the culprit

I may be going in a completely opposite direction of what is going on, but I will through my 2cents in anyway.
My experience with fuels pumps is that if the vehicle starts, the pump is good....

Does the whining continue when you let off the gas and just gradually goes away, or is it instant? If it is gradual (I have know idea how to spell that word) you might have a sloppy rear end. Where the gears aren't as tight as they used to be. Another way to maybe confirm this would be to listen for a clunck sound when you shift from park to drive/reverse or from drive to reverse.

Like I said though this may not be the problem at all. I just had a vehicle that had a problem similar to yours and a sloppy rear end was the culprit

The noise goes away gradually and yes, I do have a clunk when I go from drive to reverse. I have to be sure to wait that extra second for the tranny to go into reverse before hitting the gas or I get a bang instead of a clunk. What did it take to repair your "sloppy" rear end?

The noise goes away gradually and yes, I do have a clunk when I go from drive to reverse. I have to be sure to wait that extra second for the tranny to go into reverse before hitting the gas or I get a bang instead of a clunk. What did it take to repair your "sloppy" rear end?

Since my last reply, I drove the truck and checked a few things. First, It doesn't start until the engine gets warm. Next, I can be cruising down the road at 45 mph, kick it into neutral, rev the engine and the whining is in time with the throttle. If i leave it in neutral and leave off the gas, the noise disappears. It doesn't seem like a rear end. Some of the clunking you spoke of may be associated with some problems I'm having with the transmission. I am going to have some type of valve inside the transmission replaced. Every once in a while, the computer gets confused and my torque converter seems to disengage resulting in big bangs between gears. Shutting the vehicle off resets the computer and it acts normal again. The whining noise does not seem to be associated with that problem though. Sorry for jumping to conclusions in my first reply.

Sounds to me like it is either a bad water pump bearing, fan Belt Idler wheel or tensioner pully.

What is this valve in the transmission you are talking about and how do I change it? I think I may be having similar problems with the torque converter.

I have a 99 Silverado with a 5.3. It has 63,000 miles on it. I bought it used with 47,000. It has developed a whining noise that seems to get louder when you give it more throttle. It is worse in 3rd gear than in overdrive. If you leave off the throttle while going downhill, it virtually disappears. I have been reading some posts about the fuel filter needing changed. I will try that. However, when I turn the key on and listen, I can't hear the fuel pump running/whining. Does this still sound like a fuel pump problem?
2-3 years late on this idea, but, sounds like tail bearing at the differential. What did you find out?

Sounds to me like it is either a bad water pump bearing, fan Belt Idler wheel or tensioner pully.

With a water pump you should notice it leaking from the weep holes on the pump itself. I would lean towards one of the idler pulleys or the tensioner. Do you notice the noise if you are parked and the engine is warm?

Since my last reply, I drove the truck and checked a few things. First, It doesn't start until the engine gets warm. Next, I can be cruising down the road at 45 mph, kick it into neutral, rev the engine and the whining is in time with the throttle. If i leave it in neutral and leave off the gas, the noise disappears. It doesn't seem like a rear end. Some of the clunking you spoke of may be associated with some problems I'm having with the transmission. I am going to have some type of valve inside the transmission replaced. Every once in a while, the computer gets confused and my torque converter seems to disengage resulting in big bangs between gears. Shutting the vehicle off resets the computer and it acts normal again. The whining noise does not seem to be associated with that problem though. Sorry for jumping to conclusions in my first reply.

I would here that whinning noise when I would go to Colorado in the summer time.. When the truck was warm it was very loud. Idle or driving. Performance was not affected except for what high altitude does to performance, but when I get back to an elevation that is less than 6000, I would not hear the whinning. NOw this whining came from the fuel pump.. it was very obvious where it was comming from.

It could also possibly be the alternator. I have heard them whine like that when they start to go. It would also make sense as to why it is in sync with the throttle.

The cause of this noise is a worn out washer in the heater core inlet (it is a flow restrictor bur serves no real purpose other than causing a lot of frustration to the owner!) It's located in one of the black hoses running into the firewall from the engine compartment (I can't recall if it's the hose on the right or the hose on the left). There both located in the center just above the engine. Undo the hose, pry out the rubber washer and replace the hose.

sounds to me like a bearing in the rear diff.

There are a lot of posts on here that refer to the rear diff - a diff is a consistant whine when the car is moving and the whine will continue until it stops moving, or moves slowly.

The whining noise in this post starts up at a certain point during acceleration and can be less audible if you don't accelerate any further. It is also does not consistantly increase in pitch as the speed increases. It is consistant with something building up pressure and then continueing until the pressure subsides.

The cause of the noise is a worn out washer in the heater core inlet (it is a flow restrictor bur serves no real purpose other than causing a lot of frustration to the owner!). The flow of the water over the cracks causes the whining sound inside the cab.

The washer is located in one of the black hoses running into the firewall from the engine compartment (I can't recall if it's the hose on the right or the hose on the left). There both located in the center just above the engine. Undo the hose, pry out the rubber washer and replace the hose.

Try this simple fix - it will cost you nothing and take 2 minutes of your time and solve you a lot of headaches!