2017-2019 Duramax L5P 2500 & 3500 Parts & Accessories

The 2011-2016 Silverado and Sierra 2500 and 3500 HD trucks are some of the most capable platforms GM ever built, thanks to the stout LML Duramax engine. However, once you start adding tuning or towing at the limit, the factory Allison 1000 transmission becomes the bottleneck. At Tier One, we specialize in removing that bottleneck. We carry a complete lineup of transmission upgrades designed to help your LML Duramax hold more power and run cooler. From our race-proven built Allison 1000 transmissions and rebuild kits to high-performance torque converters, thermal bypass valves, and deep transmission pans, Tier One has everything you need to bulletproof your drivetrain. Whether you use your truck for daily driving, heavy hauling, or drag racing, we have the parts to keep your Allison shifting firmly and reliably. If you don't see what you're looking for, contact Tier One or call 602-399-5484! If your factory transmission is slipping in high gears or you are pushing serious horsepower, a stock replacement just won't cut it, so take a look at our 2011-2016 Duramax LML Complete Transmissions. The factory torque converter is often the first weak point to fail under a tune, so get better lock-up performance with one of our 2011-2016 Duramax LML Torque Converters. The Allison 1000 runs hot due to the factory thermal valve, so keep your fluid temps in check with our 2011-2016 Duramax LML Transmission Coolers. Sloppy shifts or pressure issues can be fixed with our updated 2011-2016 Duramax LML 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 2011-2016 Duramax LML Transmission Parts.