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2000 ML 320
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9 Posts
Discussion Starter #1
Hey folks. I've got a clicking or popping noise, sounds like it's coming from the driver's side front wheel. Noise occurs when accelerating from a stop, worse if going uphill (more load), is proportional with vehicle speed, then goes away at fairly low speed. I've replaced the front driver's side half axle with no relief, so it's not the CV joint. I also have a bit of a vibration when accelerating, goes away when coasting, which may or may not be related. Any thoughts? Wheel bearing / motor mount / driveshaft / ???
 

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2000 ML 430, 1999 BMW 540iT, 1993 500SL
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341 Posts
Check front ball joints (uppers). Is there any looseness/play in the steering wheel? Could be a indicator.

Else have someone else check outside while you accelerate a bit. It could be the torsion bar shims have cracked. Something i still have to fix myself here.
 

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2002 ML55 AMG, 2005 Chrysler Crossfire Coupe Limited, 1999 C280
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4,714 Posts
It sounds to me more like a motor mount issue.
 

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2000 ML 320
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9 Posts
Discussion Starter #4
While putting in the new half shaft I paid attention to the ball joints, and all seemed to be in good shape. I'll look at the torsion bar, thanks.
 

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2000 ML 320
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Discussion Starter #5
The vibration on the highway is slight, only noticeable while accelerating (goes away completely when coasting), and has been around since last summer, long before the clicking / popping. It's not necessarily proportional to engine speed, but is definitely at a higher frequency than the final drive components, so I've had motor mounts in the back of my mind for awhile. Is there a good way to check them / is it obvious if one is bad? It's more of an annoyance than an "OMG I gotta fix this thing". Thanks ...
 

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'07 C280 4matic, '06 530i, '98 ML320
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1,562 Posts
Clicking noise is a known issue with transfercase. Change the transfercase fluid.
Popping noise is a known issue with torsion bar shims. New shim-kit is available at MB dealer for around $15. I would let a professional handle the job of opening the torsion bar to replace the shims.
 

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2000 ML 320
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9 Posts
Discussion Starter #7
Thanks, is there more info re the known issue with torsion bar shims and popping? Seems like accelerating from a stop while going straight doesn't really involve the torsion bar. The noise is no worse or better when turning. I'm just trying to get my head around it all. Any other info would be greatly appreciated, thanks ...
 

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02 ML320 06 ML500
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16,866 Posts
You might have to separate problems. Aside from putting the truck on a lift, you can check the engine mounts out in the following way:

1. Engine running.

2. Place in drive

3, Set parking brake.

4. Step hard on brake pedal

5. Snap the throttle/gas pedal (push down quickly and let go)

6. Then place in reverse and check for the other side mount

If the motor mount is bad you will feel and hear a loud thump.


The second issue might be the Torsion Bar support, as previously mentioned
 

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2000 ML 320
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9 Posts
Discussion Starter #9
Yes, I agree this may be separate issues. Thanks for the notes on checking motor mounts - that makes sense.

And Aha!!! In all the discussion on torsion bar shims I was thinking sway bar, which I was having a hard time getting my head around. I forgot the springs are torsion bars, so will check that out as well.
 

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02 ML320 06 ML500
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16,866 Posts
Yes, I agree this may be separate issues. Thanks for the notes on checking motor mounts - that makes sense.

And Aha!!! In all the discussion on torsion bar shims I was thinking sway bar, which I was having a hard time getting my head around. I forgot the springs are torsion bars, so will check that out as well.
The popping sound is a clear indication of the torsion bar support, but check everything.

Remember, if you take apart the bearing to replace the support, it must be done with the front wheels off the ground.
 

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2000 ML 320
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Discussion Starter #11
You might have to separate problems. Aside from putting the truck on a lift, you can check the engine mounts out in the following way:

1. Engine running.

2. Place in drive

3, Set parking brake.

4. Step hard on brake pedal

5. Snap the throttle/gas pedal (push down quickly and let go)

6. Then place in reverse and check for the other side mount

If the motor mount is bad you will feel and hear a loud thump.


The second issue might be the Torsion Bar support, as previously mentioned

I tried this, with no thumps, so assume the motor mounts are good. Will look at the torsion bar, as well as the drivelines. The noise is proportional to vehicle speed, which makes me think it might be in the drivelines somewhere. Anyway, thanks for the help so far - will update as I run the traps ...
 

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2005 ML350
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60 Posts
Clicking noise is a known issue with transfercase. Change the transfercase fluid.
Popping noise is a known issue with torsion bar shims. New shim-kit is available at MB dealer for around $15. I would let a professional handle the job of opening the torsion bar to replace the shims.
What fluid are you using for the transfer case? I have a 2006 R500
 

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ML 350 / W163 2003
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23 Posts
Don't know if that helps but i had a clicking/popping noise that drove me mad and i couldn't figure out what it was.
It appeared at a certain speed on the highway, i found out that the plastic cover inside the wheel cover was loose and rubbed against the front wheel at a certain speed..
I replaced the screw and re-mounted it and its gone.
 

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2005 ML350
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60 Posts
Don't know if that helps but i had a clicking/popping noise that drove me mad and i couldn't figure out what it was.
It appeared at a certain speed on the highway, i found out that the plastic cover inside the wheel cover was loose and rubbed against the front wheel at a certain speed..
I replaced the screw and re-mounted it and its gone.
Interesting. Are you running aluminum wheels? Is this plastic piece part of the wheel?
 
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