The R56056 Injector Pump Drive Gear is a replacement part specifically designed for the John Deere 4039T diesel engine. This component is crucial for the proper functioning of the injector pump system, ensuring optimal fuel delivery for efficient engine performance. Made by John Deere, a trusted brand known for producing high-quality agricultural equipment, this drive gear is a reliable and durable component for maintaining and repairing diesel engines. See photos for additional part numbers to ensure compatibility.