Mishimoto Thermal Bypass Valve

2019–2026 Ram 2500 / 3500 6.7L Diesel

Part #: MMTC-RAM2-TBV

Overview

The Mishimoto Thermal Bypass Valve is a precision-engineered upgrade designed specifically for the 2019 to 2026 Ram 2500 and Ram 3500 trucks equipped with the 6.7L Cummins diesel engine. This vital component regulates the flow of transmission fluid to the cooler, ensuring your transmission maintains optimal operating temperatures under all conditions.

Unlike the stock thermal bypass valve, which is prone to failure and can lead to transmission overheating, Mishimoto’s valve features a durable, fully serviceable thermostat that opens approximately 10°F earlier than the factory unit. This promotes improved cooling efficiency without risking over-cooling, enhancing transmission reliability and longevity.

Built for Ram owners who demand dependable drivetrain performance, this valve is an essential upgrade for heavy-duty towing, extreme climates, and extended operation, protecting your transmission from heat-related damage and maintaining peak performance.

Key Features

The Mishimoto Thermal Bypass Valve offers advanced transmission fluid management and cooling enhancements, including:

• CNC-machined aluminum construction for superior durability and enhanced heat dissipation
• Replaceable, fully serviceable thermostat calibrated to open earlier than stock for faster fluid circulation
• Increased fluid flow compared to the factory valve, improving cooling efficiency under heavy loads
• Interchangeable thermostat bypass plug allowing constant full fluid flow in hot climates or demanding conditions
• Integrated cooling fins on the valve body to further reduce transmission fluid temperature
• Durable black anodized finish providing corrosion resistance and long-lasting appearance
• Compatible with both 68-RFE and Aisin AS69RC transmissions found in Ram 2500 and 3500 models
• Backed by the Mishimoto Lifetime Guarantee for peace of mind

Construction & Design

Crafted from high-quality CNC-machined aluminum, the Mishimoto Thermal Bypass Valve offers superior strength and thermal conductivity compared to the stock plastic valve. Its black anodized finish protects against corrosion and wear, ensuring reliable performance even in harsh environments.

The valve’s integrated cooling fins increase surface area to dissipate heat more effectively, helping maintain optimal transmission fluid temperatures during heavy towing or extended operation. The fully serviceable thermostat can be replaced without removing the entire valve, simplifying maintenance and allowing customization to suit specific climate or usage needs.

Installation & Fitment

Installation is straightforward and requires no modifications to the existing transmission cooling system. The Mishimoto Thermal Bypass Valve is a direct factory replacement for the stock valve on 2019–2026 Ram 2500 and 3500 models equipped with the 6.7L Cummins engine. The included bypass plug can be easily swapped using a wrench to tailor cooling performance for seasonal or climate-specific requirements.

This valve fits the following Ram models and trims:

• Ram 2500 Big Horn (2019–2024)
• Ram 2500 Laramie (2019–2024)
• Ram 2500 Laramie Longhorn (2019–2021)
• Ram 2500 Limited (2019–2024)
• Ram 2500 Limited Longhorn (2021–2024)
• Ram 2500 Lone Star (2019–2024)
• Ram 2500 Rebel (2023–2024)
• Ram 2500 Special Service (2024)
• Ram 2500 Tradesman (2019–2024)
• Ram 3500 Big Horn (2019–2024)
• Ram 3500 Laramie (2019–2024)
• Ram 3500 Laramie Longhorn (2019–2020)
• Ram 3500 Limited (2019–2024)
• Ram 3500 Limited Longhorn (2021–2024)
• Ram 3500 Lone Star (2019–2022)
• Ram 3500 SLT (2019–2024)
• Ram 3500 Special Service (2024)
• Ram 3500 Tradesman (2019–2024)

What's Included

• Mishimoto CNC-machined aluminum thermal bypass valve assembly
• Replaceable thermostat pre-installed
• Thermostat bypass plug for constant cooling option
• Installation hardware and detailed instructions

Ideal For

This thermal bypass valve is ideal for Ram 2500 and 3500 owners who frequently tow heavy loads, operate in hot or variable climates, or want to improve the reliability and longevity of their transmission. It is especially beneficial for those experiencing transmission overheating due to stock valve thermostat failure or anyone seeking to optimize transmission fluid temperatures for enhanced performance and durability under demanding conditions.

Mishimoto is a performance cooling brand offering aluminum radiators, intercoolers, oil coolers, hoses, and supporting hardware built to manage heat on hard-driven street and track vehicles. For boosted setups and towing/off-road rigs alike, Mishimoto upgrades are designed to increase cooling capacity and reliability where factory systems can become a limitation.