Major vibration when accelerating

2005 PONTIAC GRAND PRIX
240,000 MILES • 3.8L • V6 • 2WD • AUTOMATIC
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ZACKARY MERCER
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I get a major vibration when accelerating between 45-65 mph. But nothing at any other speed. I’ve had the tires balanced twice and the vibration does not come through the steering wheel but instead it’s just the entire car shaking.
Apr 12, 2019 at 11:44 AM
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ASEMASTER6371
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Good afternoon,

Does it feel like the entire car, front end, or engine related?

Could be a motor mount, Torque converter in the transmission or possibly a harmonic balancer.

Roy
Apr 12, 2019 at 12:34 PM
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ZACKARY MERCER
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Thank you.
The engine mounts look good and it feels like the front end is vibrating. It doesn’t feel engine related though, but when accelerating at the particular speeds the shaking can get bad enough to where the sound the engine creates fluctuate.
Apr 12, 2019 at 1:35 PM
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ASEMASTER6371
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Did you have someone check the front suspension for you to see if there are any worn parts?

Roy
Apr 12, 2019 at 1:41 PM
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ZACKARY MERCER
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Not yet, i do know the strut assembly is needing replacing though. And the last time i had an alignment done was almost a year ago and nothing was wrong with the front end at that time.
Apr 12, 2019 at 2:40 PM
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ZACKARY MERCER
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Update: i drove it around a little bit but i decided to open up the hood and give the car a push while in park and it caused the engine to move a good amount. Maybe the engine mounts might be bad?
Apr 12, 2019 at 3:20 PM
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ASEMASTER6371
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Yep, that sounds about right. I attached a guide for you for replacing the mounts.

https://www.2carpros.com/articles/replace-motor-mounts

Roy

Apr 12, 2019 at 3:26 PM
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ZACKARY MERCER
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I went ahead and replaced them. But i don’t think it helped with the vibration. But at least I won’t ever have to replace them again because it probably still needed it. I went ahead and checked transmission fluid and it was at a good level but very dirty.
Apr 13, 2019 at 4:18 PM
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ASEMASTER6371
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Are these the mounts you changed? The upper mounts have a left and right.



Roy
Apr 13, 2019 at 4:25 PM