Next Gen Diesel offers a selection of 2001-2005 Allison transmissions and parts that are compatible with GMC and Chevy diesel trucks manufactured during that time frame. If you want to update your old stock transmission, or upgrade to a heavy-duty model that works with a more powerful engine, we have what you’re looking for. Our selection of 2001-2005 Allison parts includes clutch hubs, input shafts, and torque converters. These expertly made parts and transmissions are made from high-quality materials, which ensures they can handle anything for years to come. We carry transmission rebuild kits, which are ideal for those who enjoy getting their hands dirty and fixing up their truck themselves. Check out our 2001-2005 Allison transmissions and parts today!