Fuel lines, engine seals and transmissions are parts that commonly break in used pickup trucks. Other common problems with used trucks include rust and oil leaks. In addition, sometimes former owners may have reset a used truck's computer to mask engine warning lights that otherwise indicate potential problems.
Fuel or exhaust line problems often go undiagnosed on older model pickup trucks and are hard to notice during a test drive. Bad engine seals often cause significant chronic problems with the engine. Problems with transmissions are usually expensive to repair, and sometimes the cost of repairing an older truck exceeds the truck's value.