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Mishimoto Mishimoto 2017+ GMC 6.6L Duramax L5P Transmission Thermal Bypass Valve Kit
Mishimoto Mishimoto 2017+ GMC 6.6L Duramax L5P Transmission Thermal Bypass Valve Kit
Mishimoto Mishimoto 2017+ GMC 6.6L Duramax L5P Transmission Thermal Bypass Valve Kit
Mishimoto Mishimoto 2017+ GMC 6.6L Duramax L5P Transmission Thermal Bypass Valve Kit
Mishimoto Mishimoto 2017+ GMC 6.6L Duramax L5P Transmission Thermal Bypass Valve Kit
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Mishimoto 2017+ GMC 6.6L Duramax L5P Transmission Thermal Bypass Valve Kit

Mishimoto
MISMMTC-L5P-TBVFF
840197710609
Transmission Coolers
20+ Units In Stock - Ships Next Business Day
$ 110.00 $ 99.95
$ 99.95

SKU: MMTC-L5P-TBVFF | UPC: 840197710609

Mishimoto 2017+ GMC 6.6L Duramax L5P Transmission Thermal Bypass Valve Kit

Upgrade your 2017-2021 Chevrolet Silverado 2500 HD / 3500 HD and GMC Sierra 2500 HD / 3500 HD with L5P 6.6L Duramax using the Mishimoto full-flow thermal bypass valve kit. This direct-fit replacement eliminates the stock thermostat that fails and blocks fluid flow to the cooler causing overheating. Experience constant transmission cooling for heavy towing and high-heat conditions with improved flow and heat dissipation.

Key Features

  • CNC-Machined Aluminum Construction: Billet 6061 aluminum body withstands high pressures and temperatures while resisting corrosion for long-term durability.
  • Full-Flow Design: Removes internal thermostat to deliver unrestricted fluid flow to the transmission cooler at all operating temperatures preventing heat buildup.
  • Optimized Internal Passages: Precision-machined channels increase fluid throughput over stock valve for faster heat rejection and lower transmission temperatures.
  • Integrated Cooling Fins: Machined fins on the valve body enhance surface area for passive air cooling adding extra thermal management.
  • Black Anodized Finish: Durable coating protects against wear with Mishimoto Lifetime Warranty covering defects in materials and craftsmanship.

Product Notes

  • Direct replacement for Allison 1000 transmission stock valve no modifications required.
  • Perfect for trucks in hot climates or frequent towing to maintain optimal trans fluid temps.
  • Kit includes valve O-rings and hardware for complete installation.

Installation Notes

  • Professional installation recommended.
  • Drain transmission fluid before removal of stock valve.
  • Bolt-on fit uses existing mounting points and ports.

This Part Fits

Year Make Model Submodel
2021 Chevrolet Silverado 2500 HD Custom
2017-2021 Chevrolet Silverado 2500 HD High Country
2017-2021 Chevrolet Silverado 2500 HD LT
2017-2021 Chevrolet Silverado 2500 HD LTZ
2017-2021 Chevrolet Silverado 2500 HD WT
2017-2021 Chevrolet Silverado 3500 HD High Country
2017-2021 Chevrolet Silverado 3500 HD LT
2017-2021 Chevrolet Silverado 3500 HD LTZ
2017-2021 Chevrolet Silverado 3500 HD WT
2020-2021 GMC Sierra 2500 HD AT4
2017-2021 GMC Sierra 2500 HD Base
2017-2021 GMC Sierra 2500 HD Denali
2017-2021 GMC Sierra 2500 HD SLE
2017-2021 GMC Sierra 2500 HD SLT
2020-2021 GMC Sierra 3500 HD AT4
2017-2021 GMC Sierra 3500 HD Base
2017-2021 GMC Sierra 3500 HD Denali
2017-2021 GMC Sierra 3500 HD SLE
2017-2021 GMC Sierra 3500 HD SLT

Why Choose Mishimoto?

  • Direct-fit engineering matches OEM specs for L5P Duramax Allison transmissions.
  • CNC machining ensures precise tolerances for reliable performance under high torque.
  • Lifetime Warranty backs every kit for peace of mind on the road.

Frequently Asked Questions

  • Q: Will this fit my 2019 Silverado 3500 HD L5P Duramax?
    A: Yes it fits all 2017-2021 Chevrolet Silverado 2500 HD / 3500 HD and GMC Sierra 2500 HD / 3500 HD models listed with 6.6L L5P engine and Allison 1000 transmission.
  • Q: What material is the valve made from?
    A: Constructed from billet 6061 aluminum with black anodized finish for strength corrosion resistance and heat dissipation.
  • Q: Does installation require special tools or modifications?
    A: No modifications needed it's a direct bolt-on replacement using factory mounting points includes all necessary O-rings and hardware professional install advised.

Shipping & Handling

  • Method: UPS Ground or USPS Priority
  • Availability: In stock - ships same or next business day
  • Packaging: Securely boxed 8 x 6 x 4 inches
  • Weight: 0.8 lbs
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