Rotary 17367 Auc20590 Compatible with or For John Deere Idler Pulley Auc11238, Auc11239 17367 Idler Pulley For John Deere Flat Composite Drivetrain Pulley Replaces John Deere Auc11239. Compatible with or For Several John Deere X300 Series. Replaces: John Deere Auc11239 John Deere Auc20590 Id: 5/16" Od: 3-1/2" Height: 1-1/2"