Mishimoto Transmission Cooler for L5P Duramax Allison 1000 Thermal Bypass Valve

Mishimoto Transmission Cooler Thermal Bypass Valve for L5P Duramax (Allison 1000) Protect your Allison 1000 — the Mishimoto thermal bypass valve replacement for 2017–2019 Chevrolet/GMC 6.6L L5P Duramax prevents overheating by ensuring reliable fluid flow to the transmission cooler when it’s needed. This premium upgrade replaces the failure-prone stock thermostat with a CNC-machined aluminum valve body, improved internal passages for greater flow, and integrated cooling fins to dissipate heat more effectively. Built for towing, heavy loads, and extreme climates. Direct fit for 2017–2019 L5P Duramax with Allison 1000 Serviceable thermostat for fast warm-up in cold weather Optional bypass included for constant cooling in hot or extreme-duty use Enhanced flow via machined internal passages Durable finish — black anodized aluminum with Mishimoto Lifetime Warranty Upgrade to Mishimoto to reduce transmission temperatures, extend component life, and maintain towing performance. Easy to install and engineered for long-term reliability.