So... I hit a rock pretty bad over the weekend :(. I was going about 100KM/h maybe less, and it was smaller then a basketball sized rock, but it did some damage and jolted me/vehicle.

I immediately pulled over and inspected for damage. I couldn't even see where it hit on the bumper! Yay! or so I thought. I turned the engine on and immediately herd 2 distinct knocks when it turned on. Then I noticed a vibration when in Park.

I tested all the tranny positions and it is evident in Neutral and Reverse, but completely gone in Drive, even if I am not giving gas and stay's gone when I drive normally. It seems fine shifting gears as well.

It is less noticeable in Neutral, but still there and quite noticeable in Park and Reverse. I can't even hear the noise from the outside, but it's very noticeable inside the van. (2011 Dodge Grand Caravan and I'm quite used to how it sounds).

Any ideas/things to look for that could be causing this?

I did a bit of research and I am hoping it's "Engine Mounts" which doesn't look to be too bad on the wallet, but I'm concerned for my Tranny which has already been replaced (and is still under warranty, but I'm not sure this would be covered).

Thank you!

  • Are you sure it wasn't vibrating before you hit the rock and you just didn't notice? Sometimes people notice all sorts of things after an incident, thinking they just started.
    – GdD
    Apr 30 '18 at 7:57
  • 100% sure, It's new. Apr 30 '18 at 7:58
  • Since there is nothing to do with drive-train that is turning while in Park, I would first check around the engine bottom pulley and possible dents in the engine sump.
    – HandyHowie
    Apr 30 '18 at 9:05
  • Do you think it's possible for engine mounts to break or come loose or that's probably not it? Most people talked about them "going bad" vs breaking Apr 30 '18 at 9:07
  • " is evident in Neutral and Reverse, but completely gone in Drive" Most likely an engine/trans mount, and most likely the mount on the front of the engine which is towards the radiator.
    – Moab
    Apr 30 '18 at 16:28

It's possible but unlikely that the engine mounts are the problem, at least they wouldn't be the only problem that needs to be addressed. An engine mount is a flexible cushion that connects the engine to the car frame, they degrade over time and it's possible that an impact could break one loose, especially if its closer to the end of its service life. That could be the cause of the vibration, and it's possible that putting it into drive could smooth that out.

However, any force that would be large enough to break an engine mount would likely break other things as well. Large rocks can dent oil pans, bash in radiators, damage suspension and steering components, brakes, the list of critical components goes on.

So as the rock has caused noticeable damage somewhere you'd be best getting this looked at by a mechanic as soon as you can. You don't want a ball joint failing at highway speeds, or your oil pan dropping out!

  • 1
    The thing is... Engine mounts are not exactly fragile. It is designed to absorb the vibrations of an engine outputting hundreds of hp. It is unlikely a rock would damage just the engine mount without leaving a giant dent in your car somewhere.
    – Nelson
    Apr 30 '18 at 16:59
  • I agree @Nelson, the dent may be underneath and hard to see, but there's bound to be other damage.
    – GdD
    Apr 30 '18 at 18:51
  • Going to get it diagnosed Friday, ill update the posts with results May 1 '18 at 8:35

The problem was a bent crossmember touching the tranny.

I was told I could continue to drive with it but would always have vibrations but it's under 300 to fix so I'm fixing it.

Fingers crossed that the vibrations go away!

Update: 300 CAD bill to fix crossmember ($120 part + 1hr labour) and noise is 100% gone! :)

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