Rattling Noise 2011 Infiniti G25when between 1000 and 1500 rpm; louder at higher speed

2011 Infiniti G25 V6 160,000 miles automatic transmission. Rattling noise gets louder with speed and happens when the car is coasting or breaking and between 1000 and 1500 rpm. It sounds like a grinding sound, metal on metal. No noticeable sound while idling or at complete stop in drive.

Current thoughts are issue with the transmission.

Any thoughts would be helpful. Thanks.

Loose heat shield would be very likely. You need a good look under the car with a rubber mallet. Tap the exhaust and see what rings or rattles. Start there.

+1

Automatic transmissions do not typically put out rattling noises.
A loose or bent heat shield is MUCH more likely to be the problem.

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Another place to look is at the dust shield at the brakes.

Thank you, I will take a look at the heat shield today.

You likely have more than one, so be sure to check under the hood, as well as underneath the car.