A bump in your trunk is the classic sign of a bad strut. As part of the suspension system, struts work to keep your ride smooth and your steering under control.

Struts are typically replaced in pairs — because chances are good that if one strut has failed; the other one is not far behind.

Failed struts can lead to a safety issue. Why? click on the link below:

Does Your Car Have a Blown Strut? (napaonline.com)