Mishimoto Transmission Thermal Bypass Valve Kit Chevrolet | GMC 6.6L 2017+- MISH-MMTC-L5P-TBVFF

The Allison transmission is the backbone of your L5P Duramax. It's responsible for transmitting large quantities of torque from your V8 diesel powerplant. This torque generates a lot of heat, and if that heat isn't dissipated, it can destroy your transmission. The transmission cooler does a good job of keeping trans fluid temperatures in check, but only if the fluid can reach it.

The stock cooling system of the Allison 1000 transmission utilizes an in-line thermal bypass valve that controls fluid flow to the transmission cooler. The purpose of this valve is to prevent transmission fluid from flowing to the cooler until it reaches operating temperature. The thermostat inside this valve is prone to failure, however, and when that happens, the fluid never flows to the cooler, and the transmission can overheat. That's why Mishimoto has developed a full-flow thermal bypass valve upgrade for your 2017+ Chevrolet/GMC 6.6L Duramax.

Our CNC-machined aluminum full-flow thermal bypass valve not only looks better than the stock unit, but it performs better too. This Mishimoto thermal bypass valve eliminates the internal thermostat, providing full fluid flow to the transmission cooler in all running conditions. This setup is ideal for owners in warm climates, those performing heavy towing, and trucks needing the best possible cooling efficiency for their transmission. The Mishimoto thermal bypass valve features strategically machined internal passages, providing improved flow over the stock valve for more effective cooling. In addition, cooling fins machined into the valve body add even more heat dissipation.

This 2017+ Chevrolet/GMC 6.6L Duramax L5P Full-Flow Thermal Bypass Valve Kit is built to last a lifetime with a durable black anodized finish and our Mishimoto Lifetime Warranty.

Features:

• Direct fit for 2017+ Chevrolet/GMC 6.6L Duramax L5P
• Installs in less than 1 hour
• Eliminates failure-prone bypass valve
• Durable CNC-machined billet-aluminum construction
• Full-flow bypass allows the transmission cooler to operate at maximum efficiency
• Helps extend transmission life and prevent overheating
• Fits with stock transmission cooler piping, requiring no modification for installation
• Integrated heat-sink fins provide unique styling and added heat dissipation
• Durable anodized finish
• Mishimoto Lifetime Warranty

• (1) CNC-Machined Billet Aluminum Thermal Bypass Valve
• (2) 7/8" X 14 Quick-Disconnect Transmission Line Fittings
• (1) Transmission Line Mounting Plate
• (1) Transmission Line Mounting Plate Bolt
• Mishimoto Lifetime Warranty

• OEM ACTIVATION TEMP C: 85??
• OEM ACTIVATION TEMP F: 185??

• Engine Codes
  • L5P
  • 6.6L Duramax
• Chassis Codes
  • 2500
  • 3500
• Fits
  • GMC Sierra 2500HD V8 (6.6L Diesel) 2017+
  • GMC Sierra 3500HD V8 (6.6L Diesel) 2017+
  • Chevrolet Silverado 2500HD V8 (6.6L Diesel) 2017+
  • Chevrolet Silverado 3500HD V8 (6.6L Diesel) 2017+

• Mishimoto does not recommend customers in cold climates install the thermostat bypass to avoid overcooling of the transmission fluid
• This performance thermostatic bypass valve only fits vehicles equipped with the Allison automatic transmission