sbaer

Well my engine was affected by the head bolt issue and that was fixed. Then the valve tappet issue showed up and that also was an easy dealer experience but my whining noise coming from the drivetrain appears to be more difficult to locate.
When driving there is this whining noise which is speed dependent. Best heard at 55-58 mph but it starts around 20mph I would say.
At the second appointment the shop foreman said he can hear it but after checking with MBUSA this is normal with 4matic in the ML63.

A long time ago I had a 190E that made the same noise and it was a bad rear differential.

Fellow ML owners: Do you have a whining noise?

RossN

Try having the Transfer Case, and front / rear Diff fluids replaced, the noise may go away. I had a similar issue with my ML55 and changing those fluids made my whining and clicking noise go away.

If you plan on keeping the car a longtime, might be a good time to go ahead and have the Transmission fluid and filter changed as well.

sbaer

Thanks for the ideas. I actually had the rear differential oil changed a month ago because the dealer mentioned that as optional and we thought we give it a shot but no change.
So I guess I could try front diff, transfer case and transmission now

ML63 AMG

You sure it's not your power steering pump? It is rpms based. If it's speed based its after the transmission (transaxle or differentials).

The only oil that will quiet down a whinning drive train is Royal purple MaxGear 75w-90, it will make any diff super quiet

vvrjrlaw

Or try the wheel bearings. They are best described as a rumbling that becomes a drone as speed increases. Remember when a dealer says that he "checked with MBUSA and its normal" its translation is " Christ I haven't got a clue!" You need to get an indie who is knowledgable with MB to check out the car. A whine/rumble is not a good thing and is not normal. It needs to be checked out and fixed before you spend more money on something that could have been avoided. Good luck!

sbaer

Thanks - that's a good idea. Took it out for a ride and it is not rpm dependent but based on speed.

@vvrjrlaw agree. I found a local Indie here in NC with good reviews and will get an appointment.

ML63 AMG

I agree on the wheel bearing issue too. If it's not steering pump it can be wheel bearing

sbaer

A second dealership came to the conclusion that the noise comes from the transmission. They say it is normal. As I don't know anyone with this vehicle I cannot compare but my wife hears it too and she normally is not annoyed by noises in cars.

ML63 AMG

I don't have transmission noise, do tranny fluid service, use standard MB fluid for tranny. Royal purple for front & rear diff

sbaer

I took the vehicle to an independent shop to get more insight on this noise and they took it on the lift and listened to various components with a stethoscope while another tech put the wheels in motion via gas pedal.
In their opinion the noise comes from the transfer case and they feel it is not normal as it can be heard inside the cabin as well.
Furthermore the tech has a GL550 2008 which exhibits the same noise and another GL550 does not make that noise in comparison. Unfortunately the tech has not had time yet to investigate.

The assumption is that the output bearing in the transfer case needs to be replaced but we are unsure if that part can be sourced individually. MB does not appear to be offering it.
While looking into options with MB on a regional service level my path may lead to either replacing the transfer case with a used one or having a rebuild done on the existing one. In Europe that is easier as there are folks that rebuild the 7G and transfer case. Have not found a place in the states yet.

RossN

On the ML55 I bought used, the Front Diff and Transfer Case made a howling or whirring noise, even a clicking noise as well. Super annoying to listen to over time even though the indy mechanic I use said he couldn't hear it.

I researched this issue and the best I could determine, was that the Transfer case was known to make the clicking noise dependent on speed, and the front and rear diff's can get noisy without changing the fluid regularly. Thru some of this research (benzworld), it was suggested to not just change the Diff fluid, but to do so multiple times. Change with fresh fluid on both diff's and transfer case and drive for about a week, then change all 3 with fresh fluid again. It's worth a shot and cheaper than swapping parts right from the start.

ML63 AMG

Try royal purple, it has been known to quiet down even the noisiest of differential or transfer cases

benzexpert

The most common point of failure is the front differential. 2006-2012 ML, GL & R series.
Mercedes only sells the complete diff, no parts or bearings.
I've sold bearing kits for hundreds of repairs on both ebay and
on my website benzexpert.com with 100% positive feedback.

In fact a local differential shop repaired mine for $500 + the bearings and seals.
No more horrible noise!
Much less than a replacement diff with the same crappy bearings. Check it out!