1997 Dodge 2500 turbo diesel - manual transmission

Why do I hear a clank when I am shifting gears? Although I hear the clank after my truck warms and appears to be more noticeable when driving at high speeds, it is still noticeable when the vehicle is when the truck is still relatively cool. Please HELP! How do I remedy the problem without having to leverage my first born and grandson?



Thanks

Tina Marie