alkrstev

Ok, so here is the deal. I have been battling with weird noises, jerks and sounds in general coming from my 02 c32 for years now. At first I had a sluggish acceleration problem, then I replaced the spark plugs and my IC pump to CM30. Then the car was acting weird and jerking at every gear on initial throttle. That did not help much, so then I replaced my gas pedal assembly with a new one. That helped a little but then my car developed a weird buzzing/droning/grinding noise at exactly 40mph. So, then I took the car to the dealership to have it checked out. BTW, I have a 20k old transmission, radiator, and torque converter(replaced under warranty) and and 18k TCU. However, I am out of warranty now, so I just want to know what is wrong with it. They find nothing wrong with the car and the transmission fluid was at the correct level and there was no mixing of fluids. So, they give me two options, either get a new TCU for the transmission, or do a torque converter/gear adaptation(reset the TCU from beginning). So, I chose the cheaper route to go with the adaptation which cost me $130+$130 for the check up. They did that, and the car had the same annoying sound at 40 mph. They told me that they did everything they could and I would have to change the TCU and change the transmission fluid in order to attempt to get rid of the noise. It has only been around 20k since the NEW TCU and the NEW transmission with radiator and torque converter was put in, so obviously new transmission fluid was put in. The throttle response is unbelievably slow and all the gear shifts are sluggish still, and on top of all of that I still have the noise when cruising at or slowly passing 40 mph that I cannot get rid of. Please give me any suggestions on what to do next cause the car is very uncomfortable to drive and I am sick of all the little problems with the Transmission/acceleration. Thanks in advance and sorry for the long description.

loudandheard

Who did the install and how long ago? Was there any warranty given? Were you having any problems when the transmission was first installed?

alkrstev

The transmission, torque converter, and radiator were installed in May, 2007 when the car had around 50k. All the work was done by the MB dealership and was given a year warranty on the work they did. There was no problems for about a year and a half to two years, then it just started getting worse and that is why I replaced the plugs, the ic pump, and the gas pedal. At this point, I am afraid that my torque converter is making that noise at 40 mph. I also have my doubts that my alternator is going out and not providing enough electricity. When the car is in automatic mode, it responds very slowly and you have to push the pedal enough to engage the supercharger, or the car does not move at all. I dont even know what to look at anymore as a fix. Maybe it will fix itself.

loudandheard

I'm assuming the grinding noise is loud enough to hear in the cab because you say "when going 40mph." Are you sure it's coming from the transmission, could it be coming from the engine bay? Some times the pulley bearings have a tendency to go around that mileage. I would try to get a mechanics stethescope or use a piece of tubing placed up to the pulleys to see if you hear any unusual sounds.

Were the MB mechanics able to reproduce the sound at 40mph? You may want to send MB a letter and tell them of your situation if it indeed is the transmission. Tell them that it was put in by MB and that it's failing after 2 years which shouldn't happen with a mercedes.

alkrstev

The noise is somewhat coming from the front of the car. It sounds like a droning sound kind of like the sound after the car jerks in W mode at 1500rpm and then makes a droning sound, but it is constant and it feels weird. I just changed the tensioner pulley underneath the guide pulley next to the supercharger pulley cause it was making noise. On a different note, I still have the original belt and dont know if its possible that the belt is making that noise. It is just weird that it is only present at 40mph exactly. The other pulleys in the car seem fine except for a somewhat wobbly crank pulley which is supposed to be normal.
I told the MB mechanics about the noise and they acknowledged it. They said they cant do anything else about it and that I would have to try to replace the TCU AGAIN, after only two and a half years, and do a tranny flush on a NEW transmission with only 3 year old 20k fluid. Maybe I should go back to the dealership and ask them to inspect it again for free.

CLKCLK

ONLY 3 years???? Do the flush again.

alkrstev

Maybe you are right CLKCLK, but I have only passed ~20k. However, I do drive the car hard almost all the time. When I was getting the car checked at MB, they showed me what my fluid looked like and it was clear and did not look burnt. However, it might be a good idea to replace the fluid and could solve the problem. How often do you replace the fluid?

SETSEROCK

Wow. Just wow. I was about to make this EXACT thread. Word for word.
Same noise at EXACTLY 40 mph (like a mechanical buzzing, whining hum)!! I have 79k on my car. New tranny under warranty at 58k!!! Same ultra sluggish throttle response (feels tranny related). Same jerking.

The tranny on my las merc died and I swore I'd never buy another merc. Not I got one and the tranny has waaaayyyyyy toooooo many bugs in it. WTF???!!!

alkrstev

I am truly sorry that you have the same problem. I did research and did not want to seem like crazy posting this but I found very little about this problem. It is annoying as hell and I can replicate the buzzing sound at 40 mph EVERY TIME I try. Since you got a new tranny as well, maybe the fluid they put in it was not up to par, or even the TCU they put in gets confused??? This car and its transmission has been tormenting me ever since I bought it. First the 1500 rpm jerk that was a slam frequently, and then all the noises and failed suspension parts, pulleys, light bulbs, and multiple other things that I can't remember now. Anyways SETSEROCK, if you fix it first, please let me know how.

SETSEROCK

doubtful. Ive had this car for less than two months. And I've already had it. I will be changing the tranny fluid... But other than that I will just sell it. the transmission and marshmallow soft suspension ruin this car.

SETSEROCK

And why exactly 40 mph???? What the f#@k??!!!

alkrstev

I just went to the MB dealer today to ask them how I can fix my problem. They told me that the next thing they can do is to add some sort of additive to my transmission fluid that might help the situation. However, I would still have to pay the $130 per hour and pay for the fluid. Another suggestion that they threw at me was that it could be the valve body that needs replacement and it would cost $1550+tax. I dont feel like throwing away ~$150 to try the fluid additive thing for something that is not guaranteed to work. I really dont know what to do now.

SETSEROCK

what is the additive? id like to add it when i change my tranny fluid soon.

how the f@#k could a valve body go out on a 3 year old AMG tranny?

loudandheard

Is there a way that any of you could get a audio clip of the sound that you are getting. I've been driving with out a radio for almost two weeks now and I have no audible sound at any speeds. The strange thing is that both of you are having the exact same symptoms and both of you have had your transmission replace with in the last couple of years.

Could it be that it was not install properly?

As for a soft suspension, you can always upgrade it, but I already have a hard time where I live with my stock suspension, Houston by the way, any tighter and my car would probably fall a part from all the bumps that we have in town.

alkrstev

The service rep did not say what the additive was, but he called the parts dept and nobody answered(I went there as well and nobody was there). He just said that if the tech was to add it to my car, they would have to hook it up to their machine and he said something about the temperature having to be correct when it is added to the tranny fluid. About the valve body, I told him the same thing, but he was insisting that they replaced many valve bodies and that they do go bad. You might want to call your dealer and ask about what this additive is. I will do that as soon as I got time maybe on Monday.

alkrstev

Loudandheard, I will try my best to take an audio/video clip of it, but I think it will be difficult to record. However, you can definitely feel the vibration when you are driving and it is the worst when you reach 40mph and leave it on cruise control. Also, at times when driving at any speed and letting go of the gas, the speed IMMEDIATELY drops fast like the car is trying to engine brake. Then I have to push the pedal a 1/3 of the way just to keep the speed from dropping.

loudandheard

I think the deceleration is normal, but I could be wrong. I know my car does it.

alkrstev

OK loudandheard, here are two videos of the buzzing sound at 40 mph. I took these videos with a G2 android phone, so the sound/picture is not great but if you turn up the sound all the way on your computer and youtube, you can hear what I am talking about. Once I get the car up to 40 mph and leave it there, you can clearly hear the buzzing/droning sound.
Video 1

http://www.youtube.com/watch?v=IA-CSptp9WA

Video 2

http://www.youtube.com/watch?v=r5h0og3luFg

SETSEROCK

I want to try putting cruise on at 40 too. I always notice as I pass 40 or when I'm dooms 40ish in a 35 mph area. I agree it would be hard to record. It sounds like its coming from behind the motor and under the dash/center console (like, oh... Right where the transmission is).

I too can replicate it every time I try.

I'm going to flush the tranny soon.

alkrstev

Let me know how it goes. I also am having the following problem: Here is the TSB: Maybe that is what caused the noise and the incorrectly functioning transmission because the insulation above the transmission may have warped and is scraping on the propeller shaft.

Body - Scraping Noise From Transmission Tunnel Area

Date: October 8, 2004

Order No.: P-B-88.30/36

Supersedes:

Group: 88
SUBJECT:
Model 202.022/023/024/028/029/033
Model 203.040/061/064/065/076/081/084/261/264/281/284/740/747/764
Model 210.020/025/055/065/070/072/074/082/083/265/282

Scrapping Noise from Transmission Tunnel Area

If you receive customer reports in the above model vehicles of a scraping noise from the area of the transmission tunnel, the insulation above the transmission may have warped and is scraping on the propeller shaft. To resolve, perform the below procedure.
1. Make a bracket to support the transmission tunnel insulation by taking a strip of aluminum approximately 2 mm thick.

2. Cut the strip 40 mm wide and 220 mm long.

3. Drill a 6.5 mm diameter hole in the center (Figure 1).

Warning! Under body components may be hot, use caution.

4. Detach central heat shield above exhaust system and slide toward the rear (Figure 2).

5. Remove nut retaining insulation (Figure 3, arrow).

6. Bend aluminum strip to conform with tunnel contour.

7. Fit aluminum strip on threaded stud and reinstall original nut.

8. Reinstall central heat shield above exhaust system.

Note: The following allowable labor operations should be used when submitting a warranty claim for this repair.

loudandheard

I tried listening to it with the vloume all the way up and I couldn't hear any thing, but it maybe the insulation scraping by the transmission.

Is it a grinding noise or more of a wine?

I got under my car to day and I have a leak close to my transmission, so I have a few new problems to deal with. I will be doing a flush and few more things as well.

alkrstev

It starts out grinding from 10 mph to around 20ish and then when it gets to around 38, the sound will change and when at 40 you can clearly hear the buzzing/droning sound. Just turn up the volume on the video and listen for the sound when my car is at 40 mph. You will hear the buzzing. When the car is just cruising at 40 mph, you can definitely hear the sound, but in real life, you can also sense the vibration from it. I think I might have the problem with the insulation scraping by the propeller shaft and causing the noise. I wonder if I take it to the dealer if it would be covered since it is a TSB, but I doubt it. From what I see, it doesnt seem that hard to do. Just find an aluminum piece with the given dimensions and put a screw in the middle of it so it holds up the insulation.

rickad

Greetings to all. I just purchased a 2002 AMG c32 with approx. 64,500 miles.
Since I've been driving the car I did notice this same occurrence. identical to
the ones posted in this forum, buzzing sound at exactly 40mph. The bulletin
that was posted does appear to be related to the issues mentioned. My question is will any MBZ dealer cover this repair if not can we address this with MBZ of America.

alkrstev

I still have not figured out the issue. I am thinking that it might be the brake discs on the car since I have the original ones and they are extremely worn and maybe the pads rub against the disc and make that noise/vibration. I will post an update as soon as I change my two front brake discs.

Chazz

alkrstev, I have had the same noise for about a year. I was hoping it was my rotors as well. I replaced them a couple months ago and the noise is still there.

I hear the noise best under very light acceleration at 40 mph.