2004 Denali XL, whistling noise when accelerating

I've a 2004 Denali XL that makes a whistling noise when I'm accelerating between 25mph and 75 mph. The noise is most noticable between 65 and 75. The noise disappears i'm on cruise control. The dealer said that the noise is normal on the 2004 sierra/yukon denali line and that it's coming from the transmission. I'm not mechanically incline but that seems very strange to me. Has anyone else experience this noise on before?

tia,
dlx04

My dealer told me it is from the front AWD unit which is hydraulically coupled. I've got the Yukon XL with Autotrac.

My dealer told me it is from the front AWD unit which is hydraulically coupled. I've got the Yukon XL with Autotrac.

i'm sorry to hear that you're having the same problem. i thought for a while there that i was the only one with this problem. sounds like there's some sort of a discrepency between the two dealers. i've autotrac on my as well. i guess i don't understand why does the noise only occurs when i'm accelerating. when i'm on cruise control or running on a set speed the noise is not

is it more of a whine, because if it is, it could most likely be your supercharger. no big deal, it's normal

is it more of a whine, because if it is, it could most likely be your supercharger. no big deal, it's normal

yes it is. thanks for your concurrence with the dealer.

no prob

I own a 2004 Denali and have been experiencing the same problems as I have read here. My Yukon makes a whining noise when accelerating as well as when cruising at say 40 mph...once the truck has shifted into the final gear. I've taken ot to the dealer 4 times and they finally diagnosed it as an exhaust problem and what I'm hearing is actually air passing through the muffler system (didn't seem right to me). In any case, the dealer threw a set of dampers on the exhaust in front of the muffler. Well, it didn't stop the noise and now they want to put another set behind the muffler...at the recommendation of GMC customer service.

It seems to me that the dampers have killed my power a little bit, so I'm hesitant to add the second set.

Any thoughts to adding these dampers...sounds like it may not be an exhaust issue at all!

Thanks,

Mike

It was annoying at first, but i got used to it.

There is a very in depth bulletin out for your concern.

The noise is your front axle. There is no supercharger in your truck as modelman states.

The bulletin number is #03-04-17-005 dated March 13, 2003, and adresses possible fixes. The most effective fix I've seen is replacement of the front drive shaft (propshaft) with a dampened, balanced version.
This has worked probably 8 out of 10 times for us.

Other documents that you can direct your dealership to are below:
Diagnostic Information and Procedure for Front Axle Noise
Diagnostic Starting Point - Front Drive Axle (Refer to SI Document ID #696970).
Symptoms - Front Drive Axle (Refer to SI Document ID #696957).
Front Drive Axle Noises (Refer to SI Document ID #700621).
Noisy in Drive (Refer to SI Document ID #700622).
Noisy When Coasting (Refer to SI Document ID #700624).
Intermittent Noise (Refer to SI Document ID #700625).
Constant Noise (Refer to SI Document ID #700631).
Noisy on Turns (Refer to SI Document ID #700634).

Just a note the part number for that dampened propshaft is #15186002.

Hope all this has helped.

GMCTech - just wanted to say a big THANK YOU for your post. It's very valuable to look at solid information from a pro in this type of setting.

Take care,
Jerry

I have a 2003 Denali that makes a whinning noise. I took it to the dealer who replaced a bearing in the front differential. The dealer said that the bearing was pitted. It still makes the noise!

Hey. I am taking my vehicle to dealer again this week for noise. This noise was not present until late last year. We got new tires, but the noise was there before the new tires.
When we first got the vehicle, there was a leak on the ground and they replaced a bearing.
At 40MPH the noise starts and gets louder with acceleration.
The dealer checked the axle last time and said it was fine.
There must be something to it if a lot of people are having the same problem.
Thanks.
I will check the bulletins.
Good luck to all.

There is a very in depth bulletin out for your concern.

Yes, there is a bulletin on whistle from engine compartment on accell. I didn't pay attention, but saw it get scanned by while checking VIS at the dealership. We were looking for another bulletin concerning the broken exhaust manifold bolt on my truck.