High Pitched Noise 5.7 Hemi

[Seph27]

Hi all, I have a 05 RWD 5.7L Magnum and am experiencing an odd noise from either one of the accessories or the transmission.

The sound seems like some kind of metal on metal contact. It is not constant but oscillates (very quickly) in pitch. It only happens with greater than ~20% throttle. If there is minimal load on the engine at any speed there is no sound. At highway speed with some throttle it is loud enough to enter the cabin. This is when it is most noticeable and sounds like an oscillating whistle/squeal. At lower speeds it is still there but can’t usually be heard unless a window is open. Happens in any gear, including reverse, when engine is under some load. The car is not throwing any codes.

Initially thought it was the alternator, and it may be. Replaced the serpentine belt and idler pulleys just in case it was something simple but no change. Took it to my mechanic who was uncertain about the source. Did a transmission service, fluid was a bit brown. Car is on its 2nd transmission, but I am the original owner. Have not noticed anything odd with the transmission. Car drives perfectly except for the sound.

Was pretty convinced that it must be either the alternator or water pump. Have been noticing the engine temp gauge jump around a bit. Depending on where the car is driven it will move back and forth from almost dead centre to about a quarter inch left centre (lowest on the highway).

The alternator and water pump are both original. Didn’t think this was a transmission issue but not sure anymore after listening to videos online. Really surprised that the transmission would not throw any codes if it was the source of this (occasionally) loud noise.

Anyone else ever experience anything like this or have any thoughts about the source?

Thanks, S.

[WilsMagnum]

front wheel bearings ...yup

[Seph27]

Hey Wils, appreciate your response. I did not believe it could be the wheel bearings. The sound only occurs when the engine is under load. If I’m cruising at 30, 50 mph, there is no noise. The noise also doesn’t sound like a wheel bearing, its a much higher pitch. More like something is rubbing.

It’s only when I give it some gas and the RPMs rise due to a downshift that the sound occurs. The volume of the sound appears to be tied to RPMs and speed.

I’m thinking it’s either some bearing in the alternator, water pump/pump pulley, or maybe the A/C clutch? Any second thoughts?

[jkelly16]

Pull the serpentine belt & spin the pulleys by hand & see if any feel funny, not spinning freely & smoothly.

[Seph27]

Hey Jkelly, did that and found one of the pulleys was sticking. Unfortunately, replacing those and the belt hasn’t changed the noise at all.