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It started recently and I'm really afraid it can be something in the transmission.
The noise only comes on when in Drive or Reverse, and today the noise was there when the car was in Park, but still more in Reverse and goes more and less as I turn the wheel. I checked the power steer fluids, all good.
Seryogai7, I recently have been having the same exact issue that you are having. I hear a rumbling/droning noise when I am in reverse or drive with the brakes pressed. Sometimes it happens when I turn the wheel, sometimes it happens when I don't turn the wheel, and sometimes it doesn't happen at all. It has me a little concerned too but I doubt it's the transmission. I'm thinking it can be a broken engine mount or maybe something with the brakes. I don't know for sure. I am going to my Mercedes dealer on Friday to check it out and do a multi point inspection. If you don't figure out what it is by then I can let you know what it could possibly be by Friday.
shadenfroh, the sound comes from under the car somewhere around the transmission area.
If you're asking if I can feel vibration on the steering wheel or any interior parts, then no, I can't feel any vibration, just the sound.
I was thinking about center support bearing, but that was before I've had my coffee
There are heat shields down there that may start to rattle if they come loose. That's easy enough to check.
Put some gloves on and start banging on the exhaust pipes/cat/resonator/muffler - try different places, angles, strength, and see if you get a sound. If you do, it means that either the exhaust is touching something other than rubber, or there's something going on inside.
Seryogai, I am not sure what could be causing your issue but I can tell you what happened with mine because the sound your car is making sounds very similar to mine. A couple of months ago I had my power steering pump replaced at the dealership. A week ago I started hearing this droning/rumbling noise coming from the front driver tire. I had my buddy check it out for me and he noticed a loose bolt on the power steering pump. The bolt kept hitting a metal part close to it which was holding a belt as well. The bolt was loose because the mechanic at the dealership tightened it too hard and it broke off. I had the roadside assistance technician take it out and I took it to Mercedes this morning. I showed them the issue and the noise is coming from the AC line which is connected to the power steering pump. Basically, the power steering pump is loose because it is missing 1 bolt which is causing the the noise on the AC line.
I would suggest trying a couple of things. Check to see if you hear the noise consistently when you press the button next to the AC called REAR. Your power steering pump could possibly be the culprit but you won't know till you check. Look for any loose bolts and make sure to pay attention to the AC line. It's a metal line connected to the power steering pump that curves to the passenger side of the vehicle. Turn your car on, hold that line tight to see if you will still hear the noise. That's the only suggestion I can give for now. I attached some photos of my issue. I hope you find out what it is and hopefully it's something small.
Thanks for the info.
I couldn't figure out the issue on my own and so I took it to the mechanic as it was already a due for oil change anyway and I had the Mercedes guys look at it.
Turned out it is a on of the driver's side catalytic converters. The honeycomb inside the cat (there are two on each pipe on each side of the car) became loose due to a hit. As they explained it could've been me hitting bumps on the road over time or someone hitting it or something.
The part costs $2200 CAD, so I guess around $1600 USD plus labor.
So basically if one of your cats needs to be replaced you will have to get the whole cat pipe which is really stupid and inconvenient and expensive. I'm sure there's a way to go around it and get away with some welding and replacing just the broken part, but I'm not gonna worry about it until I have to do my emission test.
wow that's a bad hit. I always try to avoid bumps and potholes, because anything could break at any time. good luck, hopefully you can find an inexpensive method to fix it.
05-03-2017, 07:35 PM
