Car shakes in reverse gear

Tiny
IMAGING
  • MEMBER
  • 2006 SAAB 9-3
  • 2.0L
  • 4 CYL
  • TURBO
  • 2WD
  • AUTOMATIC
  • 115,000 MILES
Recently my car has been shaking in reverse gear. It feels like it will turn off and I immediately change gears to Park. Could it be the battery?
Should I jump start it? There is a solid check engine light on
Monday, November 22nd, 2021 AT 1:10 AM

10 Replies

Tiny
BORIS K
  • MECHANIC
  • 795 POSTS
Hello,

Do these vibrations only happen in reverse? When you are stationary and put the vehicle in drive, does it not vibrate?

I suspect a possible worn engine mount or gearbox mounting.

https://www.2carpros.com/articles/how-a-motor-mount-works

This is easily checked. Simply start the engine, apply the hand brake, and foot brake.
Put the vehicle in either reverse or drive and, with the brakes still applied, press the accelerator pedal. Have someone look at the engine and check for any excessive movement. This is called power braking.

How to power brake.
https://youtu.be/bFTxfxfEeX0

Please let us know how you get along.

Cheers, Boris
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Monday, November 22nd, 2021 AT 3:46 AM
Tiny
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When driving or idling, it doesn't shake. Only when in reverse gear.
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Monday, November 22nd, 2021 AT 4:53 AM
Tiny
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What do you mean by a worn engine?
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Monday, November 22nd, 2021 AT 4:54 AM
Tiny
KASEKENNY
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Just to jump in, I think he is talking about a worn-out engine mount or transmission mount. This is correct that this would be the most likely cause of this issue.

https://www.2carpros.com/articles/how-a-motor-mount-works

I am attaching the info from the manual on these mounts. I would put the vehicle in gear and watch the engine and see if there is much movement when it is going into gear.

Please let us know what questions you have on this. Thanks
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Monday, November 22nd, 2021 AT 5:35 PM
Tiny
IMAGING
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So, would it be an engine mount or a transmission mount or both? How can I tell which one to replace?
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Monday, November 22nd, 2021 AT 7:24 PM
Tiny
KASEKENNY
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Correct. It could be one or all of them. The way to start to find this out is to lift the hood and put the vehicle in gear and see how much the engine moves.

It should not move much at all so if you see movement then a mount is most likely worn out. So, at that point you have to do the same thing with putting it in gear and watch each mount and see where you can see it flexing.
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Tuesday, November 23rd, 2021 AT 7:32 AM
Tiny
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Okay. Now, how many mounts are there altogether?
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Tuesday, November 23rd, 2021 AT 10:36 AM
Tiny
KASEKENNY
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Take a look at the attachments below. You have a mount on both sides of the engine and transaxle.

Normally you have one on the back side as well, but it looks like this Saab only has the two.
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Tuesday, November 23rd, 2021 AT 1:10 PM
Tiny
IMAGING
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Now, can I get to the from under the hood?
Do you have a video or manual for removal and installation procedures for these including tools needed and torque settings?
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Tuesday, November 23rd, 2021 AT 1:53 PM
Tiny
KASEKENNY
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I attached the locations above because I would suggest inspecting them first, but I attached the complete process below for both mounts.

Let us know what you find. Thanks
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Wednesday, November 24th, 2021 AT 7:35 AM

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