This high-quality aftermarket replacement main thrust bearing, part number AT21136, is specifically designed for John Deere engines. As a non-original equipment manufacturer (non-OEM) alternative, it offers a reliable and cost-effective solution for engine rebuilds and maintenance. The thrust bearing plays a crucial role in the engine's crankshaft assembly, preventing axial movement and ensuring proper alignment and smooth rotation. This particular AT21136 bearing is specified as 0.75mm undersize, making it an ideal choice for crankshafts that have undergone machining during an engine overhaul, restoring precise tolerances. Engineered to meet or exceed original specifications, this aftermarket thrust bearing is compatible with a wide range of John Deere engine series, including but not limited to 4039, 4045, 6059, 6068, 6076, 6081, 6090, 6105, 6125, and 6135. Its robust construction ensures durability and long-lasting performance, contributing to the overall longevity and efficiency of your John Deere machinery. Opting for this AT21136 replacement thrust bearing helps maintain critical engine clearances, protecting against premature wear and supporting optimal engine operation.