Visual/Physical Inspection

WARNING: This page is about a different car, the 2002 GMC Sierra and 2002 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
Inspect the manual transmission for the correct fluid level.
Inspect the manual transmission for fluid leaks.
Inspect the manual transmission for broken or loosen transmission mounts.