My 07 legacy began to rattle after I turned the ignition on. It's never done this, and I just had the 60k service and inspection done 2 weeks ago at the dealer, and had all tires replaced with news ones per spec.

For context, the car sat in the parking lot while it snowed and rained, creating ice that was hard and slippery - but it's done so many times before.

The grumble shows up BEFORE I even move the car - and it is only in 'reverse' (with brakes on and when I tap the accelerator a bit) that it makes a hell of a grinding noise. In 'Neutral' and 'Park', the noise disappears, and in 'Forward', the noise becomes much less noticeable.

The noise comes mostly from the middle underside of the car, but at times some of it seemed to come from the right exhaust, although no ice was visible inside it or even underneath the car.

I moved my car about in the parking lot, and can say that making turns does not produce the noise, and moving forward the grumble was only slightly noticeable if that. It was tapping the accelerator while in reverse that produced the weird and loud grinding noise.

 

I put a 15 AMP in the FWD slot (the AWD light did come on), but to no avail. Absolutely nothing changed, and the car behaved just as described above.

 

The car is not even middle aged, and until yesterday (before the ice) it ran great, without a hint of this rumble (and believe me, I've been paranoid about it since the first of my 55k miles).

 

Could it be Torque Bind, even though it's still there in FWD, and even though it's there even when the car is stopped?

 

I should note I let the car running for about ten minutes, but the problem didn't seem to improve as the car warmed up.

 

Insight is very much appreciated.

Edited January 30, 200917 yr by lifeson22

Maybe a loose heatshield? Wait till things warm up a bit and the ice melts see how things go I guess.

Ericem, that is the kind of insight I really appreciate. I'll be damned if doesn't match my problem, I hope you're right!

The car is still under warrenty right? I am sure it wouldn't hurt to go to your dealer if it REALLY bothers you. I am the same way if something isn't perfect (aka raddles, vibrations) really annoys me and I want it fixed right away.

I am assuming the noise does not happen during driving in general

I had a similar problem with my 92 loyale but only in reverse

 

I'll bet it is related to the exhaust pipe shaking upon acceleration and it vibrates against something else---the intial rpm increase torques/twists the engine and attached exhaust pipes

 

Best thing is to get under their with it on ramps (brake on and foot brake firmly applied---maybe even another vehicle pulled behind it if you don't trust the person in the drivers )and have them tap the pedal while you look/listen and feel around down there

I am assuming the noise does not happen during driving in general

I had a similar problem with my 92 loyale but only in reverse

 

I'll bet it is related to the exhaust pipe shaking upon acceleration and it vibrates against something else---the intial rpm increase torques/twists the engine and attached exhaust pipes

 

Best thing is to get under their with it on ramps (brake on and foot brake firmly applied---maybe even another vehicle pulled behind it if you don't trust the person in the drivers )and have them tap the pedal while you look/listen and feel around down there

 

Especially so since the engine twists in the opposite direction in reverse.

 

Dave