Q: Shake in front end while driving

Hi there,

Thanks for taking the time to contact us in regards to your 2008 Pontiac Grand Prix and the shaking issue you’re experiencing. Regardless of what type of vehicle you may own, there are typically five mechanical problems that cause shaking in the front end while you are driving.

• Bent front wheels
• Loose wheel bearings
• Tire and wheels out of balance
• Warped or misaligned brake rotors
• Damaged suspension parts

If you took the car to the dealership and they balanced the tires and completed a front end alignment, then hopefully they inspected the wheel bearings, CV joints and other mechanical parts that make up the front end suspension. As a mechanic, sometimes at automotive shops, a technician will complete the work that is assigned without really trying to diagnose the actual problem.

For example, it is very possible that the front tires and wheel combination balanced on the machine, however, if your tire has a slipped belt or what’s called a "radial pull", the front end will continue to vibrate. This is typically seen at speeds higher than 45 miles per hour and is very difficult to discover during a tire/wheel balance on a calibrated tire balancing machine.

Another thing to consider is when and under what circumstances you are experiencing the front end vibration. If the shaking occurs during braking and acceleration, the problem could be with the brake rotors, wheel bearings, or other suspension issues. If the problem is at higher speeds, it could be a tire problem.

There are several potential issues that might be causing the shaking in your Pontiac Grand Prix. The best advice I’d give you is to have a certified mechanic test drive the vehicle themselves so they can feel, listen, and observe what’s going on with your car to allow them to make a good diagnosis and repair of what’s actually causing the shaking. Hope that information helps you!