Gear unit with built-in parking lock unit

A gear unit to be used in combination with a power source having a hollow output shaft, comprising:

• a differential gear set having a rotation axis in common with the output shaft;
• a counter shaft fixedly including a first gear in mesh with the output shaft and a second gear in mesh with the differential gear set, wherein the first gear and the second gear constitutes a reduction gear set;
• a housing including an outer wall and a partition wall separably combined with the outer wall so as to part the differential gear set and the counter shaft from an exterior and define a single chamber, the partition wall including a bearing rotatably supporting the differential gear set;
• a parking gear fixed to the counter shaft and disposed axially opposite to the first gear beyond the second gear;
• and
• a parking lock device including a pawl pivotally supported by the outer wall and engageable with the parking gear and an actuator configured to make the pawl in a rocking motion to disengageably engage the pawl with the parking gear,
• wherein the pawl is disposed between the second gear and the outer wall, and
• wherein the second gear and the parking gear are disposed in the chamber defined by the outer wall and the partition wall.