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17-19 L5P Duramax Billet Anodized Transmission Cooler Thermostat Bypass Plug WCFab


CALIFORNIA WARNING: Cancer and Reproductive Harm -www.P65Warnings.ca.gov

Pricing: $53.35


The Stock Thermostatic Bypass For Warming Up The Allison Quickly In Cold Weather Conditions Is A Good Idea In Principle, But In Practice We've Seen The Valve Fail Forcing Trans Fluid Around The Cooler In Warm Weather Conditions That Cause Dangerous Fluid Temperatures For Built And Stock Transmissions Alike.

We'Ve Been Running This Design On Our Shop Development Trucks And With Our Built Transmissions Successfully And Are Now Making Them Available For Purchase Separately Due To Popular Demand.

Recommended For Trucks With Stock Or Built Transmissions And Performing Heavy Towing In Warm Climates To Help Keep Fluid Temperatures In Check.


  • CNC Machined Billet Aluminum Thermostatic Bypass Plug
  • Black Anodized Finish
  • High Temperature Silicone O-Ring Seals
  • Reduces Fluid Flow Restriction To Trans Cooler
  • Simple Installation
  • Experience Fluid Temperature Drops From 15-50 Degrees Fahrenheit
  • Direct Replacement Of The Failure Prone OEM Thermostat
  • Easy Swap Back To OEM Setup For Cold Weather Use


  • Fitment 2017-2019 Chevrolet / GMC 6.6 Duramax
  • Warranty 12 Months
  • Sold As Kit
  • Country of Origin USA
  • Finish Anodized
  • Color Black
  • Sealing Type High Temperature Silicone O-Ring
  • Material Billet Aluminum
  • Engine Duramax
  • Liter 6.6 Liter
  • Engine Code L5P
  • Engine Manufacturer GMC/Chevrolet
  • Engine Years 2017-2019
  • Fuel Type Diesel



Shipping Information

  • Item Requires Shipping
  • 1.0 lbs.
  • W11.0000” x H1.0000” x L9.0000”

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