SUNCOAST GM Duramax 6.6L L5P 10L1000 Transmission 2020-2024

DIESELR SunCoast 10L1000 Transmission (2020+ Duramax L5P)

The Allison 10L1000 is one of the strongest factory transmissions ever fitted to a Duramax, but in heavy-duty use and high horsepower builds, weak links still show up. SunCoast engineered the 10L1000 Transmission line to correct those shortcomings with GPZ friction technology, expanded clutch modules, and Pro-Loc valve body recalibration.

Whether you’re daily driving, towing massive loads, or pushing well beyond factory horsepower, these Category 1–3 transmissions are built, tested, and proven to hold. Each SunCoast 10L1000 build is hand-assembled with precision, vacuum-tested, and includes a deep cast aluminum pan for better cooling and longevity.

Variants

• 10L1000 Category 1 – GPZ Clutches & Deep Pan
  Entry-level SunCoast build using Raybestos GPZ frictions, steels, overhaul kit, and 4-quart over-stock deep aluminum pan. Ideal for stock to mildly tuned trucks needing better durability.
• 10L1000 Category 2 – Expanded E & F Capacity + Deep Pan
  Features a patent-pending billet “E” drum with 29% more clutch capacity, reinforced piston design, and 25% more “F” clutch capacity. Corrects premature wear issues seen in towing and tuned applications. Includes deep aluminum pan and GPZ friction upgrade.
• 10L1000 Category 3 – Pro-Loc Valve Body Combo + Deep Pan
  Full performance build with SunCoast Pro-Loc valve body and pump assembly, increasing line pressure (+60psi), 250% cooler charge, quicker TCC lockup, and expanded clutch modules. Designed for extreme towing, racing, and 800+ HP builds.