| They final stroke in a four stroke cylinder engine during which the exhaust valve is open in the intake valve is closed, exhausting the combusted gases. | |
| In a transmission, where all gears are constantly in contact and turning with one another. | |
| The hydraulic fluid used to transmit hydraulic pressure through the brake lines in a brake system. | |
| A piston pin that moves on the piston and a small and a connecting rod. It is held in place by retaining clips in the pin bosses. |