This original KitchenAid part is a common replacement part on KitchenAid mixers. This Pin is used most commonly in 4.5 quart and 5 quart models, this 7/8" cylindrical steel pin and attaches the center shaft to the planetary.
In the 4.5 and 5 Quart mixers the Replacement Grooved Pin, 4159133, is Used on the Center Shaft to hold the lower part of the shaft into the planetary.
This part replaces obsolete part numbers: 4159133 and 9705443. The WP4159133 pin has three grooves and is 7/8" long, and 1/8" in diameter.