mrobinso

Okay, I have been meaning to post about this issue I have been experiencing for quite some time, but just haven't taken the time to do it. I have 2006 C55 with 43,000 miles on the odometer. Over the course of the last 4,000 miles I have noticed that when the car is running hot, and I come to stop light or stop sign while driving, when completely stopped I hear the following noise coming from the rear center of the car (you might have to use your imagination here): tick...(1-2 second pause)... tick-tick-tick-tick-tick-tick-tick (in rapid succession, fading away as it makes the ticking noise). This sound might happen one to three times while stopped at a light. As soon as I lift off the brake and drive the noise immediately stops. This noise occurs about 1 out of every 4 times I drive. I cannot seem to pin it down to a specific climate (i.e., it seems to make the ticking noise in sub-freezing temperatures and mild temperature regardless (55-65 degrees F).

My first thought was, alright, you are at 40,000 miles, get your transmission fluid flushed. I did so. No change in the ticking noise.

Now I am thinking, alright, try replacing your differential fluid, maybe something is going on with the differential. I am planning to do this next.

I have ignored this problem for a while, with the logic that it might go away with the warmer temperatures of the coming Spring and Summer. That being said, I can't help but be concerned that with each foreboding "tick" my transmission or some other expensive component is edging closer to utter catastrophic failure.

Also worth noting, the car won't make this noise when the transmission is in Park and only seems to make the noise when the transmission is in Drive, hence why I only ever hear it when driving and stopped at a red light with my foot on the brake.

Can anyone provide some input here? I did find this thread https://mbworld.org/forums/c36-amg-c...r-my-36-a.html with a C36 owner experiencing a similar problem, but never got any answers and the issue addressed in the post was murky to begin with. Any ideas what might be causing this would be much appreciated and any thoughts as to what damage it may be doing to my car is even more greatly appreciated.

Viper98912

Suspension or brakes relaxing?

Transmission groaning?

Idk, hard to pinpoint. Can you take a video or audio sample? It'd probably be hard to hear. My honest opinion is going to be that you're just not listening to the radio loud enough that solves all my creaks and groans.

BTW, how did you like your SSB XF? I'm looking into maybe buying one this summer.

mrobinso

I think the original reason I never posted about this issue is because I had the intention of downloading a sound clip on my Blackberry but then kept failing to do so. I will make a sound recording when I get a chance. Your point about the radio is valid because I usually don't hear it when I am listening to some tunes.

I could talk forever about the Crossfire. PM me, I would be happy to discuss it with you and let you know what to look for when purchasing. The price is right right now, and since I know you are a DIYourselfer you will be fine. I wouldn't recommend the Crossfire to someone who never works on their own cars as there are relatively no Chrysler dealerships who cater to the Crossfire for warranty work. A good indy can work on it, just tell them its an SLK!

mrobinso

Anyone else? I am going to try to take a sound recording of the noise but anyone who may have an inkling of an idea, your thoughts would be appreciated.

loudandheard

I know there was an issue with some c32's where the heat shield had to be trimmed because it was touching some thing on the transmission, but I don't think I've heard of that happening on the c55.

superstar

Under chasse sounds are hard to find. Either you have to live with it, or wait until the culprit pops by itself. I have a clicking sound that is driving me nut , yet no one could point where the sound is coming from.

mrobinso

I am okay living with the noise if it simply a benign "tick" as Viper referenced (i.e. simply the sound of the exhaust expanding or something else). My concern mainly stemmed from the fact I thought the noise could be the indication of the onset of a serious problem.

Superstar, have you changed your differential fluid yet?

mrobinso

I think the simple fact of writing down my problem in this thread has cured the ticking sound. No but really I haven't heard the ticking since I started this thread. It will probably come back soon though...

gregsju29

...i know very little about Mercedes, but my VW GTI does the same thing, and it's well known that it's the fuel pump, and it's a normal occurence.

mrobinso

Thanks for the input greg. Lo and behold, when I went over to volkswagonownersclub.org there were about a 100 threads devoted to this issue for the 09 GTI and Rabbit. http://volkswagenownersclub.com/vw/s...g-Noise-09-GTI

Sounds similar to my problem. If it is as a benign as a fuel pump "running test", then I am perfectly content.

zcct04

"My first thought was, alright, you are at 40,000 miles, get your transmission fluid flushed. I did so. No change in the ticking noise.
Now I am thinking, alright, try replacing your differential fluid, maybe something is going on with the differential. I am planning to do this next."

Troubleshooting thoughts: If the ticking noise happens when completely stopped, it's certainly not the differential because nothing past the transmission is turning. If you think it might be the tranny, try sticking it into neutral or park next time you hear it and see if the noise immediately stops.

If the problem usually happens after being driven hard, it's probably just your hot exhaust system system rubbing against something as it cools down and the metal contracts.

mrobinso

Don't I feel dumb for thinking it could have possibly been the differential. Yes the ticking noise only happens after being stopped, and it would appear that the noise occurs after one or more quick hammers on the accelerator from the low end. The noise stops when the car is in park as far as I can tell, it only seems to occur when the car is in drive and stopped.

I am still planning to change my differential fluid anyway since I am at almost 44,000 miles.