So I've been have some issues with the car recently and have been fixing them. Last fix was the idler pulley and accessory drive belt yesterday and I took it out last night from point a to point b and back home. Car ran normal. Started it up this morning and everything sounded normal. After a few minutes, there is a continous clunking sound from under the car. I put it in gear and the sound is gone. The sound is not there when it's in any fear including reverse. Drives fine around the corner too, but once it's in park or neutral, the clunking sound comes on and stays on while in park or neutral. I opened the hood and it's not from up there so I assume it's not from the new pulley.

I just did a rear main seal recently and flushed the transmission fluid. There are no leaks and the car has been driving fine until now. What can this be? Please help!!!

As a side note: If I press the sports mode button, the clunking sound slows down. Still no noise in any gear while in sports mode. Only in park and neutral

 

Check the exhaust hangers and heat shields.

 

They are fine and on tight.

 

Any chance to narrow down the approximate location? Front, rear, Left, right, center? Trans mounts are firm, I assume?

 

It's coming from the center right where the driveshaft connects to the nose of the transmission.

 

Quote:
Originally Posted by CharlzO
Any chance to narrow down the approximate location? Front, rear, Left, right, center? Trans mounts are firm, I assume?

devxiav,

It sounds like CharlzO is on the right track. The area you describe is the vicinity of the transmission mount / rear engine mount. You might check for extra movement in the mount.

Cheers,

Don

 

Checked the mount and everything is on tight and no movement. Could it be the driveshaft. Maybe the bearing failed? Because if in gear with the foot on the brake while the car is on 4 jack stands, there is no sound at all. As foot is off brake while in gear, you can hear the sound. When put in park or neutral, you can really hear it clunking loudly.

 

When the car is not moving the driveshaft isn't rotating, so I don't understand why it should be making noise.

 

You are correct, it doesn't. Will a bad transmission output shaft and it's bearing cause a sound like this? But then again, the output shaft does not rotate either when parked/neutral correct?

 

Correct, that's why I was thinking exhaust system. I wonder if it's within the transmission?

 

Had the car on 4 stands today and drained the fluid and dropped the pan. There was no metal shavings or pieces in the fluid or pan, just some real small aluminium flecks (which I think is normal). Bolted everything back up and started it up again and as I waited for fluid to heat up to correct level I listened under the car to find that the rattling noise does come from inside, loudest at the output shaft/flange connected to the driveshaft. Any ideas? Car doesn't go into limp mode when driven around the block for about 2 miles either, but definitely runs rough compared to normal. Rattling/clunking sound is present while driving, but not as bad like when in P or N. What can it be?

 

I have the same car and the same problem. Have you found a solution?