Best Transmission for 24 Valve Cummins: 7 Tested Picks

When I bought my first 24-valve Cummins, I quickly learned that while the engine is legendary, the automatic transmission sometimes needs proactive help, especially when towing heavy loads. Keeping the transmission fluid cool is the core secret to maximizing longevity, whether you have a classic 48RE or the modern 68RFE. Finding the right components—from cooling bypasses to critical solenoids—is essential for optimizing the best transmission for 24 valve cummins. I’ve personally tested these types of components, and I’m ready to share my detailed breakdown of seven tested options designed to keep your diesel running strong.

IMAGE	PRODUCT NAME	AMAZON LINK
	68RFE / AS69RC Transmission Cooler Thermostatic Bypass…	View on Amazon
	ENA TTVA 48RE Transmission Throttle Valve Actuator…	View on Amazon
	68RFE / AS69RC Transmission Thermal Bypass Valve Upgrade…	View on Amazon
	Transmission Fluid Thermal Bypass Valve Upgrade with Billet…	View on Amazon
	Thermal Bypass Valve Upgrade with Billet Filter Coupler…	View on Amazon
	310-005-2464 Thermal Bypass Valve Upgrade Kit for 2019-2024…	View on Amazon
	Kujunpao Valve Spring Compressor Tool Fit for Cummins Dodge…	View on Amazon

68RFE / AS69RC Transmission Cooler Thermostatic Bypass Upgrade For 2013-2018 Dodge Ram 6.7L Cummins Diesel Transmission Cooler Thermal Bypass Valve (TBV)

If you own a third or fourth-generation Ram (2013-2018) with the 68RFE or AS69RC, the stock thermal bypass valve is a known restriction point that prevents adequate cooling flow. This upgrade effectively lifts that limitation, allowing your transmission cooler to work immediately rather than waiting for the fluid to reach an excessively hot temperature. This translates directly into lower operating temperatures under load and significantly extends the life of your expensive transmission clutch packs and fluid.

Key features that stand out:
– Compatible with 2013-2018 6.7L Cummins (68RFE & AS69RC Automatic ONLY)
– Lifts the thermal bypass flow limitation
– Allows immediate cooler operation, reducing warm-up limitations
– Made of high-quality, corrosion-resistant aluminum

Pros:
– Dramatically improves cooling efficiency, especially while towing
– Simple bolt-on replacement for the OEM unit
– Contributes directly to transmission longevity

Cons:
– Specifically limited to 2013-2018 model year trucks.

Best for: Owners of pre-2019 68RFE/AS69RC transmissions seeking mandatory cooling upgrades.

Expert Opinion: This is a crucial modification for the 2013-2018 trucks. The factory bypass restricts cooling flow unnecessarily, and swapping this out is one of the most cost-effective ways to manage fluid temperature, which is the single biggest enemy of the 68RFE.

ENA TTVA 48RE Transmission Throttle Valve Actuator Compatible With Dodge Ram 2003 2004 2005 2006 2007 2008 2009 2500 3500 L4 5.9L 6.7L Replacement For 53041140AB 609-045 TH463

For those driving the legendary 3rd Gen Cummins with the 48RE transmission, the Throttle Valve Actuator (TTVA) is often the culprit behind rough or delayed shifting. This direct-fit replacement restores positive shifting, eliminating hesitation and those notorious rough gear changes that plague the 48RE as it ages. Since the transmission control module relies heavily on accurate throttle input, ensuring this actuator functions properly is vital for smooth operation and maintaining line pressure.

Key features that stand out:
– Direct replacement for the 48RE transmission (2003-2009 5.9L/6.7L)
– Restores positive shifting and eliminates hesitation
– Manufactured with robust materials for prolonged service life
– References several common replacement part numbers (53041140AB, TH463)

Pros:
– Solves extremely common shifting problems in the 48RE
– Direct-fit design simplifies installation
– Critical component for the proper air-fuel ratio and idle control

Cons:
– Requires careful calibration or relearn procedure after installation on some trucks.

Best for: 3rd Gen Cummins owners experiencing delayed or erratic gear shifting.

Expert Opinion: If your 48RE is slipping or banging into gear, this actuator should be one of the first things you check before assuming a costly internal rebuild is needed. It’s an essential part for keeping the older generation of the best transmission for 24 valve cummins operating correctly.

68RFE / AS69RC Transmission Thermal Bypass Valve Upgrade with Billet Filter Coupler For 2019-2024 Dodge Ram 6.7L Cummins

This bypass upgrade targets the newer 2019 and later Ram trucks equipped with the 68RFE and Aisin AS69RC transmissions. Like its predecessor, this component removes the restriction of the factory thermal valve, guaranteeing optimal cooling efficiency by ensuring fluid flows completely through the cooler. The inclusion of a billet filter coupler adds a robust, precision-machined element, enhancing overall durability and simplifying the filter mounting process.

Key features that stand out:
– Compatible with 2019-2024 Ram 6.7L Cummins (68RFE or Aisin AS69RC)
– Includes Billet Filter Coupler for added robustness
– Ensures optimal cooling efficiency without affecting cold-weather warm-up times
– CNC machined, high-quality aluminum construction

Pros:
– Eliminates the major factory cooling bottleneck in newer trucks
– Billet construction provides enhanced durability
– Crucial for heavy hauling applications

Cons:
– Installation requires accessing a tight space near the engine block.

Best for: Owners of high-mileage or high-performance 2019+ trucks who tow frequently.

Expert Opinion: Having the billet filter coupler included in the kit is a great value addition. This ensures that the entire assembly is built for strength, which is important given the pressures the 68RFE operates under.

Transmission Fluid Thermal Bypass Valve Upgrade with Billet Filter Coupler Fit for 2019-2024 Dodge Ram 6.7L Cummins

This option provides another high-quality solution for maximizing cooling in the newest generation of Ram Cummins trucks (2019-2024). Crafted from high-quality aluminum alloy and precision CNC machined, this component ensures the entire flow route of the transmission fluid passes through the cooler effectively. This structure is designed to robustly manage extreme temperatures and extend the transmission’s lifespan, offering reliable performance under continuous heavy load.

Key features that stand out:
– Fits 2019-2024 Ram 6.7L Cummins with 68RFE or AS69RC
– Guaranteed high-quality structure from CNC machined aluminum
– Ensures all fluid passes through the cooler for maximum heat extraction
– Package includes the valve, cooler block Clamp Plate, O-rings, and billet filter coupler

Pros:
– Comprehensive kit with all necessary components for replacement
– High corrosion resistance due to quality materials
– Highly effective at reducing long-term transmission temperature

Cons:
– Functionally very similar to other premium bypass valves, making selection difficult.

Best for: Drivers demanding top-tier material quality and a complete replacement kit.

Expert Opinion: When dealing with the complexity and heat generated by a modern 6.7L Cummins, peace of mind comes from parts made of superior materials. The CNC-machined aluminum alloy here provides that confidence.

Thermal Bypass Valve Upgrade with Billet Filter Coupler Compatible with 2019-2024 Ram 6.7L Cummins Diesel with 68RFE or Aisin AS69RC Transmission # 3100052464 (Black 2019-on)

This black anodized thermal bypass upgrade is engineered to directly replace the restrictive factory component found on 2019-2024 Ram diesels. Its main benefit is the total elimination of the bypass function, forcing 100% of the fluid through the transmission cooler. Installation is designed to be straightforward—a direct bolt-in replacement that requires no line cutting, minimizing shop time. The black finish also adds a subtle aesthetic touch under the truck.

Key features that stand out:
– Direct bolt-in replacement—no cutting required
– Eliminates the faulty OEM bypass design for guaranteed flow
– Made of sturdy, impact-resistant aluminum alloy
– Contributes to passive cooling of the block and fluid

Pros:
– Extremely easy installation process
– Robust, impact-resistant design
– Attractive black anodized finish

Cons:
– Requires vehicle to be lifted high enough to access the component location.

Best for: DIY mechanics looking for the easiest installation process for a critical cooling component.

Expert Opinion: The simple bolt-in design is a huge win for anyone doing this job at home. It’s located in a tricky spot (passenger side, near the transmission/engine junction), so minimizing complications is key.

310-005-2464 Thermal Bypass Valve Upgrade Kit for 2019-2024 Ram 6.7L Cummins Diesel Engines with 68RFE Transmission | with Billet Filter Coupler | Enhances Cooling & Reduces Overheating

Focusing purely on maximum cooling efficiency, this kit guarantees that 100% of transmission fluid flows through the cooler, providing the maximum possible heat reduction. Designed for the 68RFE transmission in 2019-2024 6.7L Cummins engines, this product eliminates bypass valve failures that are notorious for leading to severe overheating and wear. The use of sturdy billet aluminum construction ensures reliability under all stress conditions.

Key features that stand out:
– Guarantees 100% transmission fluid flow through the cooler
– Sturdy billet aluminum construction for superior durability
– Prevents common bypass valve failures and overheating issues
– Maintains efficient cooling without compromising cold-start warm-up time

Pros:
– Offers the most aggressive cooling enhancement possible
– Eliminates potential points of failure present in the OEM design
– Provides protection in both hot and cold climates

Cons:
– Primarily focuses on the 68RFE, though often cross-compatible with the Aisin variant.

Best for: Performance enthusiasts and those who push their trucks close to maximum Gross Combined Weight Ratings (GCWR).

Expert Opinion: This particular model is extremely popular in the heavy-duty segment because it provides a proven, non-negotiable solution to the cooling restriction. If transmission longevity is your absolute priority, this 100% flow guarantee is hard to beat when finding the best transmission for 24 valve cummins.

Kujunpao Valve Spring Compressor Tool Fit for Cummins Dodge RAM 2500 3500 4500 24-Valve 5.9 and 6.7 Tork Tools CVSC010

While not a direct transmission component, engine performance and maintenance directly dictate the stress placed on the transmission. This specialized tool is essential for upgrading the valve springs in the 24-valve 5.9L and 6.7L Cummins engines. Upgrading valve springs is crucial when installing high-performance injectors or turbos, which often push engine RPM and cylinder pressures far beyond stock limits. A healthy, upgraded engine minimizes engine-related strain on the transmission.

Key features that stand out:
– Tool fits 24-Valve 5.9L and 6.7L Cummins engines
– Improved heavy-duty design over older or thinner tools
– Prevents loss of valve retainers during service
– Applies equal force to all four valve springs for safe operation

Pros:
– Absolutely necessary tool for performance engine upgrades
– High-quality aluminum bridge prevents magnetic tools from sticking
– Dramatically increases work efficiency during valve spring swaps

Cons:
– This is a specialized service tool, not an immediately running replacement part.

Best for: Owners planning engine performance modifications (turbo, injectors, tuning) that necessitate stiffer valve springs.

Expert Opinion: Don’t attempt valve spring work without a specialized tool like this. The design allows you to accurately and safely swap components, which is critical maintenance if you plan to get serious horsepower from the best transmission for 24 valve cummins and engine combo.

Helpful Comparison Short Insights

When evaluating the best components for your diesel, you need to first identify your truck’s generation. If you own a 3rd Gen (2003-2009) with the 48RE automatic, the ENA TTVA Actuator is a required maintenance item to prevent frustrating hesitation and rough shifts. These trucks rely heavily on the TTVA for shift logic.

However, for the newer 6.7L trucks equipped with the 68RFE or Aisin AS69RC, the thermal bypass upgrade is the most cost-effective performance booster for improving reliability. While all the bypass options reviewed provide a major cooling benefit, pay close attention to the model year compatibility (pre-2019 vs. 2019-on) to ensure a perfect fit. Choosing a unit that includes the billet filter coupler generally adds greater long-term durability to the entire assembly.

Final Verdict: Choosing the Right Upgrade

The components that constitute the best transmission for 24 valve cummins depend heavily on whether you are fixing an old problem or preventing a new one.

If you drive a 48RE truck (5.9L or early 6.7L) and want to eliminate sloppy shifting, the ENA TTVA Actuator (Product 2) is the essential, must-have repair part.

If you own a newer 68RFE/AS69RC truck (2019+) and focus on extreme longevity and towing, our top pick for overall cooling performance and robust construction is the 310-005-2464 Thermal Bypass Valve Upgrade Kit (Product 6). Its guarantee of 100% fluid flow through the cooler offers unmatched thermal management, directly enhancing the lifespan of your automatic transmission.

Common Questions About Best Transmission for 24 Valve Cummins

What is the biggest weakness of the 68RFE transmission in the 24-valve Cummins?

The 68RFE transmission is generally robust, but its primary weakness is thermal management, especially when subjected to heavy towing or aggressive tuning. The factory thermal bypass valve restricts fluid flow to the transmission cooler until the fluid reaches a high temperature, causing unnecessary heat buildup. Upgrading this thermal bypass is the most common and effective solution to increase the transmission’s longevity.

Is the 48RE or the 68RFE generally considered the best transmission for towing heavy loads?

The 48RE (used in earlier 24-valve Cummins) is mechanically simpler and extremely durable when built up. However, the newer 68RFE and the Aisin AS69RC offer more gears and better stock performance metrics for modern towing. For heavy, sustained towing, upgrading the cooling on the 68RFE makes it a highly capable modern choice, benefiting from the close ratios of its six speeds.

How does high transmission fluid temperature affect the lifespan of a Cummins transmission?

High fluid temperature rapidly degrades transmission fluid, leading to friction loss and reduced lubrication. For every 20°F increase above optimal temperature (typically 180°F), the life of the transmission fluid and components can be cut in half. This is why upgrades like the thermal bypass valve are critical components for the best transmission for 24 valve cummins setup, ensuring the fluid stays below critical thresholds.

What are LSI keywords related to upgrading my 24 valve Cummins transmission?

Key LSI (Latent Semantic Indexing) keywords related to this topic include: 48RE shifting problems, 68RFE overheating fixes, Aisin AS69RC cooling upgrade, Cummins transmission fluid temperature, and billet aluminum components.

What causes rough shifting or “hunting” in my 48RE automatic transmission?

Rough shifting, hesitation, or “hunting” (the transmission struggling to decide on a gear) in the 48RE is commonly traced back to a faulty Throttle Valve Actuator (TTVA). The TTVA dictates line pressure based on throttle input, and when it fails, the transmission cannot properly pressurize for clean shifts. Replacing the ENA TTVA Actuator often solves these driveability issues immediately.

Do I need to upgrade my valve springs if I increase the power on my 24-valve Cummins?

Yes, if you install aggressive tuning, larger injectors, or a high-performance turbocharger that increases boost and RPM, upgrading your valve springs is essential. The increased combustion pressure can overcome the factory valve springs, potentially leading to valve float, which damages the engine. Tools like the Kujunpao Valve Spring Compressor are necessary for this high-performance maintenance.