What would make an truck sound like dragging aluminum cans behind it when driven at low speeds?

A common cause of a truck sounding like it's dragging aluminum cans behind it at low speeds is a faulty or loose heat shield. The heat shield is designed to protect the vehicle's occupants and components from the heat generated by the exhaust system, and is usually located underneath the vehicle near the exhaust pipe. When the heat shield becomes loose or damaged, it can vibrate against the vehicle's frame, creating a rattling noise.

Other potential causes of this sound include:

- Loose or damaged exhaust components, such as a muffler or catalytic converter

- A loose or damaged transmission mount

- A loose or damaged driveshaft

- A worn-out or damaged wheel bearing

- A loose or damaged suspension component, such as a control arm or tie rod

- Foreign objects caught in the wheel wells, such as leaves or debris.

If you hear a rattling or dragging sound coming from your truck at low speeds, it's important to have it inspected and diagnosed by a qualified mechanic as soon as possible, as it could be a sign of a serious problem.