I have had my 04 xfire for 4 years and have about 35k on it. It has made this buzzing sound coming from the rear since I have owned it. It only occurs when you are accelerating slowly and only at a certain rpm and it goes away but it happens all the time. I had the rear latch replaced with the new type discussed here, adjusted the stops, checked my license plate frame thinking it was that. Any ideas? I read somewhere it could be the heat shield material above the tail pipe area, messed around did not see anything loose. I stopped bugging the dealer years ago but figured maybe post here and somebody may know or have had this noise. thanks for any help.

 

I have been experiencing similar sounds in the rear on my 2004. I only experience the sound or buzzing when I am lower than a 1/2 tank of gas. Does anyone have any feedback?

 

I get the same thing. I thought it might be the differential, but some say that it’s more than likely the latch issue or loose heat shield. I’ve not had any luck getting rid of the noise, so any input here will be appreciated.

Wish I had a better response.

 

Could it be Fuel Pump related ??

 

Honestly, one of the noisiest things in the rear hatch is the stupid 3rd brake light... on mine, at least.

I heard a buzz one day, put my hand on it, and it stopped.

Tore it apart and sealed everything with clear silicon... still buzzes occasionally.

 

My 2007 Roadster does this once in a great while when driving slowly. I have attributed it to a combination of wide rear tires/ certain speed/ and road surface. It just doesn't sound like something vibrating on the car itself.

 

You know since this subject has come up My Cross is about to turn 70,000 and about 6,000 miles ago I started noticing a low Buzzing/Grunting coming from the rear. I was thinking Diff, But It definatly Meets the criteria of what the others here are saying.

Randomly as I takeoff Between 5-15 mph a GGGGGGGGGRRRRRRRRRUUUUUUUUUUU sounds in low D but stops as I move past 15 mph or lift off the Gas.

 

What can make a noise is the rubber flap in the right rear of the car, this flap can vibrate really loudly. I was in Beaners car and he had removed all the trunk carpets and panels and that thing kicked up a storm. The flap equalizes the air pressure in the car and ventilates the interior, the heater fan would not work too well if air could not escape the car as fast as the fan blows it in.

 

What my noise reminds me of is the vibration you hear from these folks driving around with the loud bass vibrating.....of course it's not as loud as that but sounds similar....

 

I have experienced the same type of noise from my 04' coupe. Usually during acceleration @ around 30-40 MPH and again @ around 50-60 MPH (not at the shift points).

I have not been able to find the cause (have not really had the time to look for it).

Any suggestion would be great. Thank you

 

Nope. Not the fuel pump. Ive had the same buzzing issue in my 2005 coupe since new. Just had the fp replaced and its stll buzzing as always. Sorry.

 

Have you given any thought to the drive shaft bearings, axle bearings or CV joints?
Drive shafts can vibrate at certain speeds if they are out of balance.

 

I'm still of the impression it is caused by a combination of tires, speed and road surface. I can cruise around for 10 days in a row and never hear it but then, out of nowhere, this bass hum starts up ( I always wonder if it is my stereo speaker). I have Conti tires....how about the rest of you who experience this?

 

Oh.My.Bejesus!

I've been dealing with this for about 6 months. 2004 coupe, stock wheels, 78,000 miles.

My wife drove it to work one day and came home and said that it made a sound like "driving over a rumble strip" on the freeway at low speeds. A low, growling sound at slow acceleration from zero.

So, I drove it and nothing. . .because I generally have a heavy foot on the gas pedal and if you gas-it quickly, it won't do it.

Took it to the dealer and all they could find was a cupped right front tire. Ok, that'll explain some of the road noise I'm hearing and you practically sit on the rear differential, like with an Alpha Romeo Spider, and you hear a lot of rear-end background noise, can't be helped.

But this! This is starting out from zero and around 20-30 mph, if you slowly increase the pressure on the gas pedal, you can make the whole car shudder and growl.

For us older guys, we know a term used in trucking and manual transmission vehicles called "lugging," where you are slowly accelerating in a gear that's too high for the speed you're going. Like throwing it into 4th gear and you're only going 10 mph and if you gas it in this situation, it'll drag down and growl and shake and the whole drive train goes into a spastic fit of banging and clanking and jerking around.

Knowing this, I went out and I can make it do it all day long now by driving about 25 miles an hour, backing off the gas, bumping the shifter to shift up as high a gear as I can, then slowly give it gas and viola! rumble, rumble, rumble. Too much gas and, zip!, it's gone.

So, I was thinking it's a loose body panel, an exhaust system clearance problem, a heat shield rubbing somewhere. . .but then I started thinking about "lugging" and why it's happening mechanically, instead of body or frame.

Now I'm thinking the car is shifting into high gear too soon. It only does it when I'm in a high gear going too slowly. Doesn't that tell me that the trans is shifting too far up at low speeds without sensing ground speed?

Dunno, guys, this is a good one. It just feels all wrong.

 

GET A SMALL FRIENd AND HAVE HIM GET INTO THE TRUNK, then drive gently, I am not small and have ridden in plenty of trunks. Youll know which end, side the noise is from, you can not tell from the driver seat. Woody Enjoy, Woody

 

Interesting. I'm going to be more observant of this when it happens to me again...to see exactly what the speed is and where the trans is...

 

This is the "Rumble Strip Noise" or RSN for short. Do a search on a Mercedes or Sprinter forum and you will see that this is very common. Some people have had luck with changing fluid, others not. The cause of the issue is the lockup torque converter clutch which makes noise as it applies (too early in my opinion), the trans controller also never fully applies the clutch so there is always slippage. Some newer Mercedes TCMs have modified code that helps to minimize the noise but I dont think it was ever made available for the Crossfire. My car makes the noise at about 40MPH and 25MPH with light throttle, 52K on original fluid.

-Dan-

 

Good info, Dan, thanks. It's nice to know what's causing that rumble that I get every so often....I can live with it unless it caused problems down the road.

 

Well, the Rumble Strip Noise got worse over the past three weeks and I tried the other Chrysler dealer here in town for a diagnosis this morning. I took the service bulletin-looking things I printed from the mercedes/sprinter site and also suggested they change the torque converter and tranny oil, filter, etc.

They called a few minutes ago and were really polite and thanked me for providing them with the info I gathered up and said that changing a module, re-learning the acclerator codes and changing ATF would have a limited effect on the symptom they heard and felt on a test ride.

They believe that in actuality, it's the torque converter or tranny and if they find metal shavings when they pull teh trans. pan, it's going to be a trans replacement.

Thank you, extended aftermarket warranty! More later.

Here's the thing: For a while, it was just an annoyance you could accelerate through. Then it became louder and more prevalent all the while people are saying that it's a normal sound-get used to it.

It's not normal. It looks like my trans is shot!

 

DRIVE LINE CARRIER BEARING ? will cause this sound also .