OK guys and Gals, I need some opinions and expertise here. I own an '07 Ram 1500 QC 5.7, 51000km on the odo. I have been experiencing what is SIMILAR to belt noise or a bad bearing sound from the rear of the engine; a whistling noise if you will. I can hear it from below the driver and passenger side doors if I put my head down there. I can definitely hear it when I crawl under with my stethescope. There is no noise from the belt...for certain. The noise seems to be directly related to the temperature of the engine as it increases in dB as the engine gets warmer. It was most notable after having a load in the back. When I start it and the engine is cold, it sounds perfect, no noise! It does not seem to change pitch with higher RPM's.

I took it to the dealer and they told me the noise was occurring around the bell housing/cat. They called the Chrysler STAR line, or whatever the tech line is called, and they said that they are aware of the issue, and it was of no concern. Apparently it is the sound of the valve springs moving in the seats, and this creates a singing type noise, which is then echoed into the exhaust system. Hmmm...should these ever move like that? Probably not.

Not sure I should accept this answer as the truck still has warranty, and I frankly don't know if I believe it. Has anyone else had this experience and has anyone figured it out? If it really is of no concern, then fine, but man it is annoying. Has anyone experimented with different fluids? I have Syntec 5w20 in now and had PetroCan 5w20 in before that. I would be open to trying additives if it is a lubrication problem on the springs.

Any ideas would be great!
Stinkee

 

Hopefully not a trans issue, but take a look at the trans dip stick to make sure nothing is going on in there(discoloration, smell, foreign materials...).

 

I wondered the same thing. Checked the Tranny fluid and it looks good, smells not burnt. Wondered about Torque Con issues, but there is no stutter..yet...and also wondered about bearings in the TC. Also thought maybe pick-up pump in the tranny, but I don't know enough about the design to really speculate on that. Thanks for the response.

 

I had the EXACT ISSUE. I put my head under the truck and sure enough the noise was coming right from the bellhousing area of the tranny. Noise was most prominent under doors and behind engine. This is because the sound is ehoing off the firewall.
One day I started my truck up and there it was. I drove it for 25miles and then parked it. When I started it back up, it was there. Then after a week of sitting, it went away. It's either the belt on a pulley or it's something singing away internally.
I didn't have it long enough to diagnose it. It almost sounded like a fluttering pcv valve but the hum was just like a belt. I posted up a video and everything.

Make sure your idler pulley isn't super shiny, dull it up with some scotchbrite as the belt will slip and squeel of very shiny surfaces.
I have not experienced this sound twice. Just one time at around 7,000 miles and that's it.

 

Thanks Dirtydog. Glad to know I do not suffer alone. I have read some posts about exhaust manifold noise too. I dunno. Do you still have that video? If so I would like to have a look.