car shakes when accelerating over 55 MPH but doesn't shake when foot taken off gas

2001 OLDSMOBILE AURORA
90,000 MILES
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AURORA FAN
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I have replaced almost everything on the front end of this car. It run fine except for shaking when I am stepping on the gas to increase speed to go beyond 55 MPH. However, when I take my foot off the gas, it coasts smoothly, which indicates the issue is not rims, tires or shocks/struts/tie rods (which are all new).

I know the previous owner had work done to the transmission. I suspect issue has to be engine or transmission related. Any ideas ?
Oct 11, 2012 at 2:07 AM
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DRCRANKNWRENCH
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It sounds like the motor and/or transmission mounts are bad. You can check the engine mounts by;
putting the car's parking brake on
opening hood and get a line of site on engine
start car end rev engine in neutral and see how much it moves and what kind of noises it makes when it comes to rest
Put the car in gear and give it just enough gas to make it start to lunge which will load the motor and make it move.
If it moved more than an inch or two the mounts or a mount is failing. When one mount fails it wuickly makes the other mounts faill as the load of the eninge is distributed to the mounts still able to hold a load. So, if the motor made a noise when it came to rest and moved excessively the mounts need to be replaced as a group. That is all engine mounts and tranmission mount all replaced at the same time.
The only other ideas I have are that the alignment is bad on the car and the, "TotalToe" is not adjusted correctly.
You may have bad axles or wheel bearings.
But, you must eliminate via process and with your mileage these parts are dure for replacement.
Oct 11, 2012 at 2:17 AM
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It was the drive axle. When the guy was changing out the shocks, instead of removing the drive axel, he twisted/pullled it out of the way to make enough room to change the shock and struts. Doing so, he poped a bearing out and that was what was causing the problem.
Nov 2, 2012 at 12:26 AM
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DRCRANKNWRENCH
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That is too bad that that happened. You have to be carefuel with CV axles or they will slip out of the bearing carrier. Although I cannot see how the tech did not motice that the problem had occurred as it is pretty obvious when it happens. At least you got it fixed.
I am glad it all got sorted out.
It is always good to hear that things went well and got taken care of.
Come back anytime you need anything as we are always here to help.
Thanks
Dr. C
Nov 2, 2012 at 3:35 AM