Mishimoto Transmission Cooler 03-09 Dodge Ram 5.9L / 6.7L Cummins | Increased Cooling Capacity | Transmission Cooling Upgrade

Overview

The Mishimoto Transmission Cooler for 2003-2009 Dodge Ram 5.9L and 6.7L Cummins engines is engineered to protect your transmission from the damaging effects of excessive heat. Whether your Ram is a heavy-duty tow vehicle, a hardworking fleet truck, or a daily driver, maintaining optimal transmission temperatures is critical for longevity and performance. This direct-fit cooler replaces the stock unit with a robust solution designed specifically for these Cummins-powered trucks.

Built around a stacked plate core design, this transmission cooler offers superior durability and thermal efficiency. Mishimoto’s engineering approach focuses on increasing fluid capacity and core volume significantly beyond stock specifications, resulting in more effective heat dissipation. The cooler also addresses a common failure point in the factory system by incorporating a fully serviceable thermostat that can be easily bypassed, ensuring consistent cooling under all conditions.

For Dodge Ram owners, this upgrade means enhanced transmission reliability and extended service life, especially under demanding conditions like towing or heavy hauling. The increased cooling capacity reduces the risk of overheating, which can lead to costly transmission repairs. Mishimoto’s solution provides peace of mind and improved drivetrain durability, making it a practical and essential upgrade for Cummins-powered Rams.

Features & Specifications

This Mishimoto transmission cooler is engineered for 2003-2009 Dodge Ram 5.9L and 6.7L Cummins trucks and features a stacked plate core design. Constructed from high-quality aluminum, it delivers superior heat dissipation and increased fluid capacity for owners seeking reliable transmission cooling performance.

• Brand: Mishimoto
• Product: Transmission Cooler 03-09 Dodge Ram 5.9L / 6.7L Cummins
• Part Number: MMTC-RAM-03SL
• Fitment: 2003-2009 Dodge Ram 5.9L / 6.7L Cummins
• Material: Aluminum
• Finish: Black powder coat
• Construction: Stacked plate core
• Origin: Made in China
• Core Volume Increase: 212% greater than stock
• Fluid Capacity Increase: 244% greater than stock
• Thermostat: Fully serviceable and bypassable

Key Benefits

• Cooling Efficiency: Significantly larger core volume and fluid capacity improve heat dissipation, preventing transmission overheating.
• Durability: Stacked plate aluminum construction offers long-lasting reliability under heavy-duty conditions.
• Thermostat Serviceability: Easily accessible and replaceable thermostat prevents common failure modes seen in stock coolers.
• Direct Fitment: Designed specifically for 2003-2009 Dodge Ram 5.9L and 6.7L Cummins, ensuring hassle-free installation.
• Transmission Longevity: Maintains optimal fluid temperatures to extend transmission life, especially during towing or heavy use.
• Maintenance Friendly: Thermostat port allows quick servicing without removing the cooler from the vehicle.

What's Included

• 1× Mishimoto Transmission Cooler 03-09 Dodge Ram 5.9L / 6.7L Cummins
• Installation hardware
• Fully serviceable thermostat installed
• Installation instructions

Installation & Compatibility

Installation of the Mishimoto transmission cooler is straightforward with direct-fit design tailored for 2003-2009 Dodge Ram 5.9L and 6.7L Cummins models. Basic hand tools are sufficient for most installations, making this a DIY-friendly upgrade for experienced enthusiasts. The serviceable thermostat design allows easy access for maintenance without removing the cooler. No modifications are required, and the cooler integrates seamlessly with the factory transmission fluid lines.

• Professional Installation: Recommended for those unfamiliar with transmission fluid systems
• Modifications Required: None
• Verify Compatibility: Confirm fitment for your specific model year and engine variant

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