Strange Engine Noise

[05YukonDenaliXL]

Thank you very much for your suggestion. I have done some heavy towing during our move from CA to TX. I towed a 24' Car Hauler 4X (one way loaded, back empty). But I recall having the differential fluids replaced before each loaded trip. I will check my records. Again, thanks for your suggestion.

 

[05YukonDenaliXL]

Hello,
Yes, the front & rear differential fluids have been changed, and also the transmission fluid about a year ago. I have only put about 20k miles after the fluid changes.

Do you think it is going bad?

 

[05YukonDenaliXL]

Hello Friends,
A quick update. I took it to a nearby shop. The shop told me that the noise is coming from the crankshaft. I was also told that maybe the wrong fluid was used during my last flush. I was told that the noise may be permanent, but nothing wrong with the crankshaft. I had the fluid flushed, and replaced. The shop also put some type of treatment to help. But the noise is still there.

Any thoughts? Please help. I want to keep the vehicle.

 

[Mr. Merk]

In the 6+ years I've been at a GM dealership, that crankshaft failure and one more would make two I've heard of.

Try again.

---------- Post added at 05:28 PM ---------- Previous post was at 05:27 PM ----------

Are you sure they said crankshaft? What did they flush?

 

[Chiggy]

My guess is the front diff bearings.

 

[SLCHOE]

Hello Friends,
Recently with the cold weather in TX, I started hearing a strange noise from the engine. The noise is heard on cruising speed and with a very small amount of pressure on the gas. The noise goes away on high speeds (freeway 65 - 75mph). The noise sounds very similar to a small car on reverse. I hear it also when decelerating to a stop.

Has anyone had this noise before? What can be making that noise? How can I fix the issue? Your help is appreciated.

Pull the serpentine belt off and check all of your pulleys to spin smooth and freely ESPECIALLY your alternator. The crankshaft noise thing sounds like bs to me. If there was severe crankshaft issues, you'd hear it at all rpms.

May also be a transmission issue.

Good shops have a "chassis-ear" which is basically 4 microphones and a receiver. They can mount the mics at the suspect areas and drive the car to speed when the noise occours and using the receiver, it helps narrow down the source.

 

[ccapehartusarmyINF.(ret)]

thats my question are you sure they said "crankshaft failure"
becuase ive never even heard it referred to like that
plus any crackshaft issues are usually catastrophic becuase the tolerances are so tight

 

[SLCHOE]

Can you get an audio recording of the noise?

 

[05YukonDenaliXL]

Thank you ALL for the new suggestions, and tips. I will try again when I get back home this weekend. I will also try to see if I can get an audio recording. Once again, I appreciate all your feedback.