The Spicer 1710 Series Half Round Greaseable Universal Joint ensures you are Ready for the Road Ahead™ by allowing drive shafts to move up and down with the suspension while your semi truck's shaft is moving. Boasting compact engineering, this heavy duty replacement u-joint ensures power can be transmitted when the driveshaft is not in a straight line between the semi truck's transmission and drive wheels. Experience superior life and decreased maintenance time/costs of this universal joint with 180° positioned zerks positioned on both sides for consistent lubrication without rotation of driveshaft.