Transmission Technology- Manual Transmissions

Manual Transmissions (also known as stick shifts) transfer power from
the engine to the wheel through the use of a clutch system. Unlike
the torque converter in an automatic transmission, when the clutch is
engaged in a standard transmission a direct link is created from the
motor to the wheels. (That's why the engine stalled when you forgot
to push in the clutch at that stop sign). As long as the fluid remains
good a manual transmission usually last quite some time, although
clutches usually wear out around 100,000 miles or so.

When a manual transmission is overhauled most of the wearable parts
such as bearings and syncros are replaced and the gears are
inspected and reused if in good shape. Add a new clutch and you're
ready to hit the road again.