Loud thump noise when transmission is shifted into reverse?

LIONELL8732

MEMBER
2007 MERCURY MILAN
2.3L
4 CYL
2WD
AUTOMATIC
195,000 MILES

When I shift the transmission into reverse, I hear a loud thump from the transmission. I recently replaced both axles and some transmission fluid leaked out, but this had been happening before I replaced them. So, will I need a transmission fluid and filter change to see if that helps? It also does it when accelerating but no service engine light is on.

4 Replies

KEN L

MASTER CERTIFIED MECHANIC
47,536 POSTS

It sounds like you have a transmission or engine mount that is torn/worn out. Here is a guide that can help, and I have included the engine mount locations. To confirm the mount issue, you can lift the hood and then have a helper start the engine and transfer the transmission between drive and reverse to watch for excessive movement. You can shoot a quick video with your phone so I can see the movement to help with the confirmation. That way I can tell for sure what's going on. You can upload it here with your response.

https://www.2carpros.com/articles/fixing-loud-thump-noise-when-shifting-transmission-into-reverse-a-step-by-step-guide

Check out the images (below). Please let us know what happens.

Images (Click to make bigger)

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Sunday, May 7th, 2023 AT 2:07 PM

LIONELL8732

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143 POSTS

Here is a video.

Video (Click to make bigger)

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Sunday, May 14th, 2023 AT 8:23 PM

KEN L

MASTER CERTIFIED MECHANIC
47,536 POSTS

Thanks for the video, yep the engine/transmission mounts need to be replaced. You can see the engine move excessively. That should take care of the noise.

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Monday, May 15th, 2023 AT 10:06 AM

LIONELL8732