06 ML350 Grinding Noise When Driving

[LeroyMB]

Mine is an 06 ML350. It's been an excellent car so far. But lately, it starts giving some strange, unusual noise. For a couple days, when the car is speeding up above 25 mph, there is a noticeable grinding noise coming from under. The grinding frequency increases/decreases with speed (like the sound of something stuck within a fan). The grinding noise is still heard when the engine is turn off, with the car coasting in neutral. Have anybody experienced the same thing ? LeroyMB

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[zampolit]

possibly wheel barrings? look under the car to make sure nothing is dragging, but take to a mechanic asap for grinding noises if you can't visually see the problem.

[Benzo 003]

I would lean towards the brake system depending on the last brake service. To test the wheels bearings, drive along about 25-30 mph. Cut the wheel back and forth hard enough to shift the weight onto each front wheel. If a front bearing or hub is bad, you will hear and feel it.
To check the brakes for a frozen caliper, 25-30 mph and left go of the wheel and see if the vehicle pulls left or right. If no pull, with hands off the wheel, ease the brakes on and observe.
Third, get the car up off the ground and give the wheels a spin. It must be in neutral obviously, use wheel stops or all four up on stands at once.
Visually inspect the brake rotors for obvious gouging and/or uneven wear.

[LeroyMB]

Thanks for all the answers
It was the front right wheel bearing that creates the noise
MB service charged $700.00 to repack the bad bearing
L

[Benzo 003]

Ouch ! 700.00 sounds like you got repacked too......sorry to hear but glad it's fixed.

[cmitch]

My grinding noise turned out to be the front differential and it is being repaired now.

[Benzo 003]

Oh my....sounds very expensive, please post a cost if you dont mind.

[Rohit Singh]

Hello Leroy,

I bought a used ML350 from MB owned SMART CAR dealership three months ago. It has only 45K miles. I did not bother to get it checked by the third party mechanic thinking how the MB related people can cheat me. Anyway, within days I started hearing a grinding noise like something stuck in the front tires. I hardly drove the car. I brought it back to the dealer and their mechanic said it has something to do with the front-right brake rotter. The sales person who sold me the car wasn't there to take care of it and then think its a minor problem I decided to return later. All of a sudden I had to take a trip overseas and on my return when I went back the dealership was alredy shut down and moved to their main operations in San Francisco. I took the car there and they looked at it and found nothing wrong with the brakes or the car. Trusting them I brought the car back to hear the same noise again withing hours. I brought the ML-350 back to the dealership and drove with a mechanic and with Gos's grace he acknowledged hearing the sound that was bothering me. They kept the vehicle overnight for more investigation and gave me the bad news next day that the front differentials are broken and to be replaced at the cost of $4200!! MB USA won't take care of it as I bought it used from Smart Cars and "As is"!! When they say as is..that doesn't mean they had declared the problem beforehand. Anyway, I will have to fight this battle or cough up $4200 to take care ogf it.

Originally Posted by LeroyMB

Mine is an 06 ML350. It's been an excellent car so far.
But lately, it starts giving some strange, unusual noise.
For a couple days, when the car is speeding up above 25 mph, there is a noticeable grinding noise coming from under. The grinding frequency increases/decreases with speed (like the sound of something stuck within a fan).
The grinding noise is still heard when the engine is turn off, with the car coasting in neutral.
Have anybody experienced the same thing ?
LeroyMB

[rj1]

My 2006 ML350 has 27,500 miles and now is also is making a loud metal against metal grinding noise that appears to be coming from wheels (maybe). I noticed noise happening only twice on slight incline, but also occurred on level pavement. May be happening at higher speeds, but can clearly hear it when going slower. Doesn't happen all the time. Took it to the dealer, but the noise didn’t occur for the mechanic. 25 minutes on the road after leaving the dealer, a slight burning smell was noticed along with the noise. Pulled off the road into a parking lot and turned off the vehicle for 45 minutes. Upon restart and continuing 25 minute further drive to home, no problem was experienced. Will return to dealer. Hoping metal-grinding problem is not a differential or great expense issue. Any ideas?

[lesdana]

I had the exact same thing happen to my 2008 ML320CDI. Same noise, at 25mph+ it sounded like I was the flight leader on a B-29 bombing run. Then the MB dealer dropped the real bomb. The front differential is bad. The unit costs $2900. Luckily it is still under warranty. However, it makes and extend warranty look mighty attractive...

[schmick325]

Originally Posted by rj1

My 2006 ML350 has 27,500 miles and now is also is making a loud metal against metal grinding noise that appears to be coming from wheels (maybe). I noticed noise happening only twice on slight incline, but also occurred on level pavement. May be happening at higher speeds, but can clearly hear it when going slower. Doesn't happen all the time. Took it to the dealer, but the noise didn’t occur for the mechanic. 25 minutes on the road after leaving the dealer, a slight burning smell was noticed along with the noise. Pulled off the road into a parking lot and turned off the vehicle for 45 minutes. Upon restart and continuing 25 minute further drive to home, no problem was experienced. Will return to dealer. Hoping metal-grinding problem is not a differential or great expense issue. Any ideas?

How did you end up going with this problem?

My ML has started making a metal on metal grinding noise. Appears to be coming from the left side and i've noticed that I can only hear it when going straight ahead or turning right. Turning left makes the noise go away.

Only noticeable at low speeds and there is no vibration or other noises, even on the freeway, so I don't think its the front diff. I had the diff oil done 8000 klms ago as well and there were no filings in it.

My guess is a left hand front wheel bearing or disc dust sheild rubbing.

Car is it at Benz tomorrow so I hope they can find it.

[GregW / Oregon]

Originally Posted by Rohit Singh

Hello Leroy,

I bought a used ML350 from MB owned SMART CAR dealership three months ago. It has only 45K miles. I did not bother to get it checked by the third party mechanic thinking how the MB related people can cheat me. Anyway, within days I started hearing a grinding noise like something stuck in the front tires. I hardly drove the car. I brought it back to the dealer and their mechanic said it has something to do with the front-right brake rotter. The sales person who sold me the car wasn't there to take care of it and then think its a minor problem I decided to return later. All of a sudden I had to take a trip overseas and on my return when I went back the dealership was alredy shut down and moved to their main operations in San Francisco. I took the car there and they looked at it and found nothing wrong with the brakes or the car. Trusting them I brought the car back to hear the same noise again withing hours. I brought the ML-350 back to the dealership and drove with a mechanic and with Gos's grace he acknowledged hearing the sound that was bothering me. They kept the vehicle overnight for more investigation and gave me the bad news next day that the front differentials are broken and to be replaced at the cost of $4200!! MB USA won't take care of it as I bought it used from Smart Cars and "As is"!! When they say as is..that doesn't mean they had declared the problem beforehand. Anyway, I will have to fight this battle or cough up $4200 to take care ogf it.

How did this get resolved? You'll see another thread here and at Benzworld about '06 differentials going out at low miles. Seems to be a trend, and I'm afraid mine may be one of them.

[skpatel]

Well, I have gone through the same routine as some of the above have gone through. I bought the car at 45,000 miles still under warranty. I started hearing grinding noise. I took it to dealer and told him about the noise. The dealer said nothing wrong with the vehicle it may be the tires making noise. I asked to check wheel bearings. They said it is fine. By the time it got worse, I was at 55,000 miles and out of warranty. I changed the tires but the noise continued. Finally, at service B dealer told me there is grinding noise because of a bad differential. Total cost $3,500. I should have second opinion but I trusted my dealer and have it replaired. 1 week after replacing differential, the noise came back. I took it back to dealer. Guess what! now it is a bad bearing. Repair cost $600. I believe it was misdiagnosed to begin with and they replaced the differential for no reason. In essence, have second opinion before you approve expensive repairs. Also, if you are having differential repaired, have them replace the bearings as well. May be it cheaper that way and avoid future troubles. Suspect the bearings first. By the way, it drive nice and very quiet after the bearing replacement. Too early to tell but I will update my post.

[GregW / Oregon]

Originally Posted by skpatel

Well, I have gone through the same routine as some of the above have gone through. I bought the car at 45,000 miles still under warranty. I started hearing grinding noise. I took it to dealer and told him about the noise. The dealer said nothing wrong with the vehicle it may be the tires making noise. I asked to check wheel bearings. They said it is fine. By the time it got worse, I was at 55,000 miles and out of warranty. I changed the tires but the noise continued. Finally, at service B dealer told me there is grinding noise because of a bad differential. Total cost $3,500. I should have second opinion but I trusted my dealer and have it replaired. 1 week after replacing differential, the noise came back. I took it back to dealer. Guess what! now it is a bad bearing. Repair cost $600. I believe it was misdiagnosed to begin with and they replaced the differential for no reason. In essence, have second opinion before you approve expensive repairs. Also, if you are having differential repaired, have them replace the bearings as well. May be it cheaper that way and avoid future troubles. Suspect the bearings first. By the way, it drive nice and very quiet after the bearing replacement. Too early to tell but I will update my post.

What bearings are yhou referring to, wheel?

[Johnnike3]

06 ML-350 B-29 Run 2. Bought car almost new in 06 12k miles and now went through Dealer diagnostic Flak attack Whining noise first diagnosed as wheel bearing elected to delay an see what developed 2 days later got God awful grinding noise on left front Shut it down an had towed to dealer they diagnosed front differential but first needed 4 wheel speed sensors to correct fault codes for ABS an ESP lights My response was I found it very unusual to think sensors went bad all at once when Front diff was causing speed problems to computer Paid 800 for sensors and having diff replaced by reasonable transmission shop 2006 were all standard with all wheel drive I hope this problem won't ever come back before I sell it. Pick up next week 68000miles. 5/1/2013