Hello all. I recently (last Wednesday) purchased a silver '04 Crossfire 6-speed coupe with 48,000 miles on it. I am the second owner and the 70,000 mile/7 year power-train warranty still applies. I love my car so thats why I was disturbed when I got out on the beltway and once I got into 6th gear going over 50 mph a high pitched humming noise started emitting from the back of the car! One of the wheel wells possibly though not sure? Any ideas? Brand new tires by the way (contis). Thanks!

 

Sounds like gear whine in the differential to me. "Goose" the gas a little bit while you're driving. You should hear it while accelerating and not hear it while decelerating. Mine does it at about 75 mph.

It's a warranty item so you can probably get it replaced if you want. I personally am going to live with it for a while because I'm not sure any of the dealers in my area are competent enough to replace it.

 

By "goosing" what do you mean exactly? I was thinking the same thing myself. From what I have read on Crossfire forum I am afraid to take it in and then it end up being the same or worse than when it started. Can you explain what causes this gear whining in the differential?

 

Check to see if there is a song that you like on the radio. Then turn down the volume and see if it was you humming along with it. LOL. Just kidding...
I have no idea.

 

It sounds like its coming from the rear of the car. I am just wondering how concerned I should be about it. Any advice?

 

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Is Celine Dion in the trunk?

 

Why does she humm?

 

With this group, you have to be careful what questions to ask...

On a serious note, it sounds like you rear end. take it to the dealer.

 

I mean accelerate a bit and then let off the gas. The whine is caused by the gears in the differential being misaligned at the factory.

 

mrobinso... bobs is 100% correct. It's a known issue on some early build '04 cars. I had the same issue and my entire rear end was swapped out... noise gone. Check out this thread and click on the attachments in the first post to see copies of my work orders.

https://www.crossfireforum.org/forum...rear+end+noise

 

Also could be that annoying BUZZ / HUMM from the heat shield aluminum dimply garbage that wraps above the mufflers... Then of course it might not be... LOL.

Impossible to tell unless we hear it... Put your video camera in the back hatch, record the noise, post the sound on youtube...

Also, do what AMGLOVER said, it will narrow down the problems...

 

Everyone thanks alot for your input. I took AMGLovers advice and here is what happened.

1.) The noise of the hum wasn't affected by the rpm increase or decrease.

2.) the heat shield/wheel well molding etc. seemed perfectly and tightly attached.

3.) when I retracted the spoiler at speed after it automatically rose the noise stayed the same.

And perhaps this last one will shed light on the problem.

4.) When i shifted into neutral at speed while the humming noise was occurring it would immediately stop. I hit the gas in neutral going about 65 and still there was no sound. However once I returned the car into gear the humming once again returned!!

Hopefully somone understands what might be going on. Obviously it sounds as if previous posts are correct it being the gear differential is off? Help!!

 

ben47 I just got done reading your thread. It sounds like bobs was exactly right as you said. It also sounds like a pretty big repair. This "gear whine in the rear end differential"... would it be covered by my 7 year/70,000 mile power train warranty? It seems as if it should!

 

It is covered by your warranty. Take it in.

 

Wait guys... before your send him down the tunnel of dealership hell... Bare with me here... When my car was stock there was a HUMM / BUZZ between 60 mph & 67 mph that came from the rear end... It only happened while holding the speed, no acceleration / deceleration, nor while putting the car in neutral at the 60-67 mph speed...

Not to say that this is the problem with his car, but mine turned-out to be some sort of harmonics that vibrated the heat shield above the muffler during very specific speeds... It took me a few weeks to figure it out... Just another opinion...

 

Hi to All,
I've your same problem... the mmm noise coming directly from the differential, only when I'm pushing on the gas and over 60 mph... I don't now if mine car is covered by 7/70K warranty...
Is not amazing travel with this kind of noise and in any case I don't want to risk a big damage.
The car is a 11-2003 with 40 000 km.
Now I'll live it in the box for 4 or 5 weeks, I'm going to follow a job in Qatar, but when I'll be back home I need to discover what to do.
The problem is that chrysler's mechanics in my town has never made maintenance on a crossfire.

Any suggestion?

 

Its called resonance (natural vibration). If the differential or any other component produces the same frequency sound as that of the natural frequency of the heat shield, the heat shield will vibrate causing / adding to the buzzing. It is possible.

 

Well it certainly sounds most likely to be the differential. However if it is a resonance problem would there be a way to decrease the vibration from the heat shield myself? Possibly dampening the noise? Thanks.

However I just put in a service request at my local Chrysler dealership for Thursday afternoon (keep your fingers crossed its my first time using them as I just purchased the car last week). Armed with print outs of repair orders from ben47 I am prepared for battle.

 

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