The best suspect is a collapsed engine mount. That's not a safety issue but the constant over-flexing of hoses and wiring harnesses can lead to other failures. One of the mounts limits how much the engine can rock when you switch between reverse and drive. It is two metal brackets with a rubber isolator in between to dampen engine vibration. That rubber part deteriorates over time, then the metal parts bang against each other.
You might be able to prove this by placing the transmission in "park", opening the hood, then trying to push the car forward and backward by hand. You'll see the engine rock a little, but if it moves a lot, you'll likely hear the mount banging too.
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Tuesday, July 21st, 2015 AT 10:08 PM