My vehicle shakes when I hit bumps at 40 mph or higher. I completed front end alignment, replacement of both front/rear shocks and struts. Repair shops will gladly take your money, but will not fix the problem. Instead, they will tell you a hundred different reasons for your issue, that each cost a great deal. I just want to know what is going on and get my vehicle fixed (as any normal person would. I have utilized one of your mechanics (who I was very pleased with), but I'd just like to know the problem for my own sake.
My car has 187000 miles.
My car has an automatic transmission.
There could be a combination of faults creating the shaking effect you are feeling. Certain tire defects, particularly internal belt damage or separations, as well as irregular tire wear will cause vehicle shaking, or shimmy, and such could be "set in motion" as dynamic imbalance once you hit the bump and the steering axis changes. Theoretically, when a vehicle is presented for alignment such is ONLY attempted by the shop if the suspension is perfectly tight. Otherwise an alignment is useless. In your circumstance, despite the fact that an alignment was done, the steering rack and all suspension components would still have to be newly evaluated to get to the root cause. Another possibility is, if the motor mounts are loose, the vehicle might shake when you hit a bump, as the engine bounces around, so that possibility should be checked, too. If you desire that this problem be diagnosed by a certified Mechanic, dispatched by YourMechanic right to your location, please request a vehicle suspension diagnostic and the responding certified mechanic will get this resolved for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.