knocking sound from front of the car when standing still in drive.

[nuss]

Hi I have a cb7-91 automatic with a f22a3 engine.

There is a strange rattling or knocking sound coming from the front of the car when i'm standing still with the brake depressed and gear in drive or reverse.

If I shift to neutral or park there is no sound.
When I start putting load on the engine and start driving the car the sound goes away.

Does anybody have any thoughts of what it could be??

[dahubby]

if you could post a clip of the sound it would help. Its hard to say what a sound could be without actually hearing it...

[illinois_erik]

motor mounts are bad (front/rear). that knocking is the motor moving around. or it could be your exhaust dancing around.

you can check the mounts easily by yourself, with the car off and in park, just go to the front and hood up, start rocking the car back and forth, if the motor moves more then say a 1/2 inch the mounts are donion.
youll be able to see it very well and might even get a knocking if you get the boat rocking.

[nuss]

Thanks for the replies.
It is gone now and I can't make it come back intentionally.
But i can feel a knocking from time to time last time when I decelerated around at 100 km/h on the freeway.

I tried to rock the car but I have good suspensions so I can't get it rocking so much. But when I did so I couldn't notice any movement of the engine.

Any other suggestions?

I was thinking the transaxle. The former owner did not change oil in it as it was supposed to.
It lead to the car not slipping in to the gears but after the oil change "all was well".
Perhaps something got damaged any way?

[I'm A Yunginn']

Thanks for the replies.
It is gone now and I can't make it come back intentionally.
But i can feel a knocking from time to time last time when I decelerated around at 100 km/h on the freeway.

I tried to rock the car but I have good suspensions so I can't get it rocking so much. But when I did so I couldn't notice any movement of the engine.

Any other suggestions?

I was thinking the transaxle. The former owner did not change oil in it as it was supposed to.
It lead to the car not slipping in to the gears but after the oil change "all was well".
Perhaps something got damaged any way?

I had a similar noise not to long and a quick look under my car showed me that my CV Axles were torn. After I swapped them out no more noise! If you're getting serious vibrations that could mean it's your axles, well in my case that's what it was.

[Tishock]

Pull and push on the intake manifold to rock the engine. If it is your engine mounts it wont take too much effort to make it knock.

[tm123]

bad crankshaft pulley maybe?
mine sounded fine when at idle but in gear stopped it knocked bad rubber was dried and rotted out