grinding noise

[MlPR]

I thought the noise i was hearing from the underside of the car was the axle support bearing. Yesterday I replaced it and its still there . You can hear the noise when accelerating slowly. Its gone after 5 mph or so. It doesn't "grind" if you just roll in neutral. Help!

[MlPR]

Can the noise be coming from the transfer case? BTW, low range ins not engaging

[stoncold_26]

Interesting you mention the noise from underneath. I think my ML430 may have the same noise, but I only hear it when the car is in drive or reverse. Rolling slowly in neutral, the noise stops. Has anyone given any more insight to this? Have you found out anything? I've been told it could be my catalytic converter, but why would being in neutral be any different?

[MlPR]

Hi Stoncold 26,

now that you mention the catalitic converter, I know one of them in my truck is leaking. However, Im not sure the noise sounds like its related to the catalitic converter. I will go to a muffler shop and have that fixed and let you know if the noise went away. Later.

[stoncold_26]

Thanks for the reply. Please let me know what happens. I understand that the ML's are known for having some catalytic converter issues. I'm considering having mine looked at as well. Keep me posted.

[Ron in SC]

I had a Cat problem where it was leaking and you could hear a little exhaust leak when the vehicle was started up.

My friend has a 430 S and his car made a rattling sound. I diagnoised it as a failing Cat. The noise is not present all the time. The dealer comfirmed that the Cat. has failed and he will get a new one under warranty. The dealer claimed to him the Cats. were backordered nationally and as soon as they are available his will be installed.

[MlPR]

I fixed the leak today and the grinding noise is still there. Otherwise the truck runs fine. Good luck.