2010 Accord: Rattle In Reverse

[Phishin]

So when I shift my car into reverse with the engine running, I heard a gravely rattle. When I put it in Park, Neutral, or Drive....the noise goes away.

Of course, there a slight difference between having the car in Drive (some vibration, but no noise) vs. Neutral or Park. But when in Reverse, there's an audible sound.

Car has 265k miles on it. I just replaced both front hub assemblies because I had a bad wheel bearing...but I don't think this is related, or is it?

 

[michaelluscher]

Exhaust heat shield rusted loose?

I4 or VCM equipped V6? VCM V6 has notoriously expensive and failure prone engine mounts

 

[Kira]

Is there a difference in the gravely sound between shifting into reverse and remaining stationary vs. moving in reverse?

 

[JohnnyG]

That's the typical sound that a bad motor mount makes. That is why michaelluscher replied the way he did.
We used to check for bad motor mounts by putting the car in the offending gear (usually reverse) hold the brakes, and apply throttle.
Someone need to be outside the vehicle, with the hood open, to visually check for movement of the motor itself.
DO NOT have anyone standing in front OR behind the car while doing this test.
In fact, make sure there is plenty of open space both in front and behind the car in case your foot slips off the brake pedal, or it's not pressed hard enough to hold the car.

Could also be a loose heat shield, as he said.

 

[The Critic]

Belt Tensioner. Try running vehicle without Drive Belt to confirm.

 

[Phishin]

May have found the problem on my lunch break. I'll report back later.....

 

[Kira]

...long lunch!

 

[Phishin]

So when the front hub assemblies were replaced, I had them replace a leaky AC line so I could be ready for the upcoming summer weather.

From the factory, the rubber AC hose comes AWFULLY close to the alternator pulley. When they replaced the line, it was even closer. And although the engine mounts are old, they are NOT that sloppy, but just worn enough that when I put it in reverse, the engine tilts just enough for the hose to touch the alternator pulley.....causing the noise that I was hearing.

It was an easy fix with a few zip ties.