1986 Ford Thunderbird Ticking noise

When my car is in park it's pretty loud. When i put it in drive it gets quieter but then louder and faster when i accelerate. It sounds like a pencil being tapped on a desk. From what I can tell, it sounds like the noise is coming from right below the driver seat. It's not from the engine itself. It is a very consistent tick. I had my exhaust system inspected and no leaks were found. Any ideas?

Thanks