Odd noise while in drive

[underdog1924]

I had the front motor mount replaced and cam seal fixed about 2 weeks ago and this noise has been happening ever since. When my 95 ATX is in park, neutral, or reverse it's fine, quiet, clean. But when I shift it into drive this noise comes up that sounds like something's grinding or rattling. The sound seems to be coming from the center to right area of the car. You can feel the vibrations with it. It's low in tone and sometimes it's loud, other times not so loud. Though the sound does seem to flucuate with the temperature. Also it lessens the longer it drives and goes away some when you use the gas. The tranny was rebuilt last November. Any ideas? I can't think of any. headbang Thanks for the help.

Matt

<small>[ April 08, 2003, 02:15 PM: Message edited by: underdog1924 ]</small>

 

[sdpatt]

Check your exhaust system for clearance to the engine and body.

 

[DougLee25]

It could very well be your catalytic converter shield. Check to see if that's vibrating around.

Doug

 

[underdog1924]

Could the exhaust cause it the sound only when in drive not any other gear. Could you help me see how that would work? I can't visualize it. When we get rid of this damn freshly fallen snow I'll take a look. Thanks

 

[Huntervf]

With the car in park or neutral there is no load on the driveline (i.e transmission, wheels etc.) When the car is in reverse the wheels spin backwards, and for every action there is an equal & opposite reaction. Therefore the torque required to spin the wheels backward will want to spin the engine forward. Vice versa, with the car in drive the wheels want to spin forward so the effect on the engine is to twist it backward. To see a clearer example of this you can pop your hood, start your car, put it in drive and hold the brake tight while you apply the gas. You'll notice the front of your engine twisting upward as your driveline get "loaded" from applying the gas. Since the engine is transversely mounted your entire exhaust system will flex as the engine moves forward and backward, and you likely have a loose heat shield on your catalytic converter that's vibrating & possibly contacting the underside of your SHO when you have it in a forward gear. It's a very common occurance, my 95 MTX had the same thing happen as did my 96 Contour.

 

[underdog1924]

Cool...I got it now. I had a small amount of exhaust work done and now my mufflers hang a little lower (not by choice). Perhaps that has caused the other end to be raised enough to hit the motor. Thanks for the help.