2025 Ram Heavy Duty Set for Major Cummins Diesel Update

Ram is preparing to introduce its refreshed 2025 Ram 2500 and 3500 Heavy Duty trucks, and the biggest changes lie beneath the surface. While the exterior gets updated front-end styling and the interior receives minor improvements, the 6.7-liter Cummins turbodiesel engine is set to undergo significant upgrades to enhance its performance, efficiency, and durability.

Transmission Upgrades for Better Performance – 

One of the standout updates for 2025 is the switch to the ZF PowerLine™ 8-speed automatic transmission, which replaces the outgoing 68RFE 6-speed and Aisin AS69RC 6-speed automatic options. This new transmission is expected to deliver smoother shifts, better fuel efficiency, and improved towing capabilities, offering a more robust solution for heavy-duty truck owners.

Significant Engine Improvements –

The 6.7-liter Cummins engine itself will receive multiple upgrades. Sources from HDRams.com reveal that the engine will feature a redesigned cylinder head with external injectors and fuel rail lines, enhancing both efficiency and reliability. Its iron block construction ensures durability under demanding workloads, while glow plugs replace the intake manifold grid heater, providing better cold-start performance.

The intake manifold has been re-engineered for improved airflow, and top-loaded cartridge filters for oil and fuel will simplify maintenance. Additionally, the high-pressure fuel pump has been redesigned to address reliability concerns seen in previous models. Another major improvement is the inclusion of a Holset™ variable-geometry turbo (VGT) with a 10-blade design. This advanced turbocharger optimizes exhaust gas pressure and airflow to the engine, ensuring better power delivery and responsiveness, particularly when towing heavy loads.

The new Cummins will be the sole variant available for both the 2025 Ram 2500 and 3500 models.

These details were highlighted on The Truck Show Podcast with Lightning and Holman, which provided key insights into the upcoming Cummins updates.

Cummins Pricing Matches the 2024 High Output Model – 

The 6.7-liter Cummins will remain an optional upgrade for $12,595, according the latest dealer guides. This pricing matches the 2024 High-Output (H/O) variant in the Ram 3500. Buyers opting for the Cummins will now benefit from the ZF PowerLine transmission as standard equipment with no additional charge, adding significant value to the package.

Competitive Challenges for Ram Heavy Duty – 

The timing of these updates is crucial for Ram, as the brand faces challenges in the competitive heavy-duty truck market. Sales of Ram trucks in the U.S. fell by 19% in the first nine months of 2024, with only 268,666 units sold compared to 332,440 during the same period in 2023. In contrast, Ford sold 550,835 F-Series trucks, and General Motors (GM) moved 641,794 Chevrolet Silverado and GMC Sierra pickups during the same timeframe.

Anticipated Debut at the Detroit Auto Show – 

The 2025 Ram 2500 and 3500 Heavy Duty models are expected to debut at the 2025 Detroit Auto Show on January 10th. This event mirrors the launch of the 2019 Ram Heavy Duty lineup, which also made its debut in Detroit. With these extensive updates to its engine and transmission, Ram aims to attract buyers and regain momentum in the fiercely competitive heavy-duty truck segment.