I have a 2004 Sable with the DOHC engine. The car has 125,000 miles on it. Recently I had the rims, tires replaced and balanced, and new shocks and springs (Quickstrut). The car vibrates at 75+ MPH. Took the car back to Belle Tire and they said all wheels are balanced…and it could be a drivetrain problem. I noticed when I start the car there is a squeaking noise while the engine is turning over. Once the engine is started I hear the squeaking noise when I stop the car, when I go over bumps, and when the car is going over 75 MPH. I am thinking this may be the engine mounts. While the car was off and in park I rocked the car back and forth, I noticed the engine moves back and forth and the squeaking noise occurs while the engine is rocking. This is not the worst movement I have seen but enough to cause a squeaking noise. I also started the car and had a helper shift between drive and reverse. While going from reverse to drive the engine moves towards the firewall quite a bit and the squeaking noise occurs. While going from drive to reverse the engine barely moves and the squeaking noise does not occur.
From what I have read the rear mount takes most of the stress and breaks first. Is the passenger rear mount a real PITA??? I have average mechanical abilities. Does this job require superman strength??