Mishimoto Full-Flow Thermal Bypass Valve Kit for Select Chevrolet/GMC 2017-2019 (6.6L)

Fits select 2017-2019 Chevrolet Silverado and GMC Sierra 2500 HD / 3500 HD (6.6L).

Protect your Allison 1000 transmission from heat-related failure with the Mishimoto Full-Flow Thermal Bypass Valve Kit. The factory L5P Duramax cooling system uses an in-line thermal bypass valve that restricts fluid flow to the cooler until operating temperatures are reached. When the internal thermostat in the stock unit fails, it can prevent fluid from ever reaching the cooler, leading to rapid overheating and transmission damage.

The Mishimoto upgrade replaces the restrictive factory unit with a CNC-machined billet aluminum valve that eliminates the internal thermostat entirely. This ensures full fluid flow to the transmission cooler at all times, making it an essential upgrade for trucks used for heavy towing, operation in warm climates, or high-performance applications. The valve body features strategically machined internal passages for improved flow and external cooling fins to assist in heat dissipation.

• Eliminates the failure-prone factory internal thermostat
• Provides constant fluid flow to the transmission cooler for maximum efficiency
• CNC-machined from 6061 billet aluminum with a durable black anodized finish
• Features external cooling fins for additional heat dissipation
• Straightforward installation typically takes less than one hour
• Includes Mishimoto Lifetime Warranty
• Manufacturer Part Number: MMTC-L5P-TBVFF