Hi guys,
I have a problem, I can hear a strange sound under the car when I put my car on "D" or "R" (it doesn't really matter) but still pushing brakes. I've attached video to make it easier for you:

http://www.youtube.com/watch?v=Zh7Mms4SzOU

And I don't know what's the problem is..
What is that knocking sound?
Engine? Transmittion?

P.S. My car is 2004 AT 65k miles on it

 

Still same power at high rpm ?

 

Wow... that is an ugly sound.
Can you raise the car (like on four jack stands) and then start it?
That way you can get underneath and possibly narrow it down.
Could be the transmission or anything in the drive train like bad u-joints.
But that would be dependent on if the car is in motion or not.


If the sound isn't audible while in park, then I doubt its the engine.

 

thats not normal. if its the engine, you are still under warranty.

 

Sorry to say it but it sounds exactly as an RX-8 with blown rear rotor I heard last year.

 

if it was blown , it would do that in park too.

Its only doing it in drive or reverse because there is a transmission load on the motor.

I would say probably torque converter or something in the driveline has come loose or broken. Does the car still drive fine?

Did it suddenly start doing this one day or been progressive?

 

^yeah if it was a blown rotor then it would do it all the time and prob have a CEL on.....any dash lights on? I'm also saying torque converter or something in that aspect

 

It sounds like a Chinees tractor, not a John Deere so I can't help you.

 

Thanks for all of you, guys.

I will answer the questions:

Not sure, cause I'm driving it usually in 2000-4000 rpm range. And this is AT... so I'm not racing))

Unfortunately no... I live in Russia, Mazda do not offer warranty on these cars here... I wish I could have 100k miles warranty, but... everything that happening to this car - is out of my pocket... new engine is about 7000$ here, and it's about 3500$ to repair the old one (without changing rotors, housings and etc..) =(

I saw this sound recently, because, like I said you can hear it only when pushing brakes and car is on "D", that's a transmission loads on the motor. If you release brakes - you will not hear it. On "P" or "N" that's ok, I mean no sounds like that.

No, no CEL or any other "problem" lights on a dash...

 

That does sound bad. Does this happen while in D when you are not moving? My car while not moving, will vibrate worse in "D" ,"M", "R" then if not moving and in "N" or "P". When I am in neutral or park while idling I have very little vibration, however when I am sitting still in D, M, or R I will get an infrequent rough idle or vibration that will buzz and shake a little. My theory has always been that it is something with the torque converter or transmision, though as soon as I hit the gas it stops. Also my transmission shifts beautifully, and doesn't clunk ever going into "gears" while stopped. So for me it might not be tranny. No idea. All I know is I've never heard an idle like the video the OP posted. That really does sound bad..my rough idle is like a moderate buzz.

That sounds like you're in the cab of an old diesel pickup.

 

Thanks dude)

In your case it's just an engine mounts 100% - change them! And you'll be fine... no vibration at all.

In my case... hm... that's not the engine idle sound. That's the sound under the load + holding brakes.