2004.5-2005 Duramax LLY 2500 & 3500 Parts & Accessories

Your 2004.5-2005 LLY Duramax Silverado or Sierra 2500 or 3500 still has plenty of life left in it, but the stock 5-speed Allison transmission is often the limiting factor when it comes to reliability and performance. Tier One offers an extensive lineup of drivetrain upgrades for 2004.5-2005 Duramax LLY trucks that will help your truck shift better, run cooler, and hold more power. We carry everything from our very own built Allison 1000 transmissions and rebuild kits to essential durability upgrades like high-performance torque converters, thermal bypass valves, and deep transmission pans. Whether you are towing heavy loads or just want to keep your classic Duramax on the road, Tier One has the parts you need. Check out our built Allison transmissions. If you don't see something you're looking for, contact Tier One or call 602-399-5484! If your factory transmission is slipping or you are pushing serious horsepower, a stock replacement just won't cut it, so take a look at our 2004.5-2005 Duramax LLY Complete Transmissions. The factory torque converter is often the first weak point to fail when you start adding torque, so get better lock-up performance with one of our 2004.5-2005 Duramax LLY Torque Converters. The Allison 1000 runs hot due to the factory thermal valve, so keep your fluid temps in check with our 2004.5-2005 Duramax LLY Transmission Coolers. Sloppy shifts or pressure issues can be fixed with our updated 2004.5-2005 Duramax LLY Valve Bodies. Finally, whether you need a deep transmission pan for extra fluid capacity or rebuild components, we have the parts you need in our section of 2004.5-2005 Duramax LLY Transmission Parts.