Where is the oil sending unit on a 1998 Chevy pickup?

The oil sending unit on a 1998 Chevy pickup is located on the passenger side of the engine block, near the oil filter. It's usually a small, cylindrical unit with a single wire connected to it. However, the exact location might vary slightly depending on the engine (e.g., 4.3L, 5.7L, etc.).

To be absolutely certain, refer to a repair manual specific to your truck's year, model, and engine. A Chilton's or Haynes manual will have diagrams and detailed information. You can also often find diagrams online through sites like AutoZone or other parts retailers by searching for your specific vehicle details.