{"product_id":"tc-remanufacturing-hd1221-automatic-transmission-torque-converter","title":"TC Remanufacturing HD1221 Automatic Transmission Torque Converter","description":"\u003ch2\u003eOverview of TC Remanufacturing HD1221 Torque Converter\u003c\/h2\u003e\u003cp\u003eThe TC Remanufacturing HD1221 automatic transmission torque converter is engineered for heavy-duty Chevrolet, GMC, and Hummer trucks. Designed to meet specific fitment requirements, this torque converter offers reliable performance for models like the Silverado 2500 HD and Sierra 3500 Classic.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eBillet cover construction for enhanced durability\u003c\/li\u003e\n\u003cli\u003e13.50-inch converter diameter\u003c\/li\u003e\n\u003cli\u003e11.50-inch bolt circle for secure mounting\u003c\/li\u003e\n\u003cli\u003eMilled flats hub type with 25 spline count\u003c\/li\u003e\n\u003cli\u003eMounting thread size of 10mm x 1.5 with 6 threaded holes\u003c\/li\u003e\n\u003cli\u003eStall speed range between 1700-1900 RPM\u003c\/li\u003e\n\u003cli\u003eVisible black sticker markers for easy identification\u003c\/li\u003e\n\u003cli\u003eCompatible with multiple converter codes including 221 and 29530317\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eTechnical Details and Specifications\u003c\/h2\u003e\u003cp\u003eThe HD1221 torque converter features a billet cover that improves structural integrity and heat dissipation, essential for heavy-duty applications. Its 13.50-inch diameter and 11.50-inch bolt circle ensure proper fitment and balance within the transmission system. The milled flats hub type with 25 splines provides a precise connection to the transmission input shaft, while the 10mm x 1.5 mounting thread size and six threaded holes secure the converter firmly in place. The pilot diameter measures 1.703 inches, aligning with factory specifications for Chevrolet, GMC, and Hummer models. The stall speed range of 1700-1900 RPM is optimized for towing and heavy load conditions, improving torque multiplication and vehicle responsiveness.\u003c\/p\u003e\u003ch2\u003eCompatible Vehicles and Applications\u003c\/h2\u003e\u003cp\u003eThis torque converter is compatible with a range of Chevrolet, GMC, and Hummer heavy-duty trucks, including:\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eChevrolet Silverado 2500 HD and 3500 HD (including Classic models)\u003c\/li\u003e\n\u003cli\u003eGMC Sierra 2500 HD and 3500 HD (including Classic models)\u003c\/li\u003e\n\u003cli\u003eHummer H1\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eIt is designed to replace torque converters with converter codes such as 221, 29530317, and 29540484, ensuring a direct fit and reliable operation.\u003c\/p\u003e\u003ch2\u003eCommon Issues Addressed by the HD1221 Torque Converter\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eTransmission slipping under heavy load or towing conditions\u003c\/li\u003e\n\u003cli\u003eDelayed or harsh engagement during acceleration\u003c\/li\u003e\n\u003cli\u003eOverheating of the transmission due to inefficient torque transfer\u003c\/li\u003e\n\u003cli\u003eVibration or shuddering at stall speed\u003c\/li\u003e\n\u003cli\u003eFailure of original torque converter components due to wear\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eInstallation Notes and Tips\u003c\/h2\u003e\u003cp\u003eWhen installing the HD1221 torque converter, verify the converter codes to ensure compatibility with your vehicle’s transmission. Proper alignment of the milled flats hub and spline count is critical for smooth operation. Use the visible black sticker markers to confirm correct orientation during installation. Torque all mounting bolts to manufacturer specifications using the 10mm x 1.5 threaded holes. It is recommended to inspect the transmission fluid and replace it if contaminated during the installation process.\u003c\/p\u003e\u003ch2\u003eQuality Assurance and Warranty\u003c\/h2\u003e\u003cp\u003eTC Remanufacturing produces the HD1221 torque converter to meet OEM standards for durability and performance. Each unit undergoes rigorous testing to ensure proper stall speed and mechanical integrity. While specific warranty details are not provided, TC Remanufacturing products typically come with a limited warranty covering defects in materials and workmanship. Consult product documentation or contact the manufacturer for exact warranty terms.\u003c\/p\u003e","brand":"TC Remanufacturing","offers":[{"title":"Default Title","offer_id":51841318879413,"sku":"HKFT-HD1221","price":637.64,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0628\/1442\/1173\/files\/DU_HD1221_Fro.jpg?v=1774728014","url":"https:\/\/www.partcatalog.com\/products\/tc-remanufacturing-hd1221-automatic-transmission-torque-converter","provider":"PartCatalog","version":"1.0","type":"link"}