By the mid-1980s, Dodge Ram was in trouble. It was known for its workhorse pickups dating back to before the legendary Power Wagons. But now it ran out of diesel engines to bolster its engine range and, perhaps more importantly, its rugged image. Developing a new diesel engine from scratch was out of the question. Although an all-new 1994 truck design was still years out, Dodge couldn’t wait. Thus, in the late 1980s, an unlikely arrangement was created with the legendary Cummins Diesel in Columbus, Indiana.
For decades, Cummins had offered diesel engines for heavy-duty semi-trucks and commercial applications, but never delved into the consumer pickup truck market. Why would it? The big three automakers were fully capable of doing it themselves.
What year did the first Ram Cummins diesel engines come in?
But not Dodge right now. So this partnership proved valuable to both companies and led to a range of applications for Ram Cummins diesel trucks. In 1989, the first engine from the partnership was the iconic 5.9-litre, 12-valve Cummins. First offered in the medium-duty D200 and D300 trucks, it had 160 horsepower, but torque had a 400 lb-ft growl.
As diesel engines are more advanced with better technology, this is now considered a rudimentary design. Some of this is attributed to the fixed geometry turbocharger. But that worked well for consumers because the engines were such that self-repair was easier than on later versions. And the engine was a workhorse, yet offered about 25 mpg. It continued production of this most successful diesel engine for years before developing the second generation Cummins ram.
This was done specifically to match the unveiling of its all-new 1994 truck, the first in over 20 years. While the 5.9 Cummins was largely unchanged, there was a new addition, the Bosch P7100 “P-pump” mechanical injection pump. It was backed by a 47RH four-speed automatic in 1994 and 1995, the NV4500 five-speed manual from 1994 to 1998, and the 47RE four-speed automatic from 1996 to 1998. In this configuration, the 5.9 provided bulletproof service for a few more years under Ram 2500 and 3500 hoods. .
Mid 1998 to 2002 5.9-litre Ram Cummins diesel
Then in mid-1998, a new 5.9-liter Cummins diesel, nicknamed the “53 block” was developed. It had a 24-valve design, again with Bosch injection. But this was the electrically controlled VP44 injection unit. Unfortunately, the unit caused fuel shortage problems, and this was not the only fault.
The block name 53 stood for the number 53 that was cast into the blocks. Unfortunately, this identified a fatal flaw, as cracks would form until the coolant literally flows out. According to Raybuck, it is caused by thin water jacket walls, which develop cracks from the pressure of coolant cavitation, corrosion and pressure within the block. Despite these flaws, the new engines were able to deliver between 400 and 500 horsepower using aftermarket modifications. The 2001 through 2002 High Output engines had 10 horsepower more and 45 lb-ft more torque.
Enthusiasts think that every year of this generation of owners will come in handy, as long as they don’t have a 53 block but a manual gearbox. The two manual transmissions offered were the NV4500 manual transmission in 1998 through 2002 and the NV5600 six-speed manual transmission in the 2001 and 2002 HO models.
Third Generation 2003 to 2007 5.9-litre Ram Cummins Diesel
This era offered both quad-cabs and Mega-Cabs for the first time from 2006. The 5.9-litre diesel’s new common-rail injection system gave it more power and torque. These engines were also smoother and quieter than the earlier Cummins units. They also saw aftermarket tunes and components that boost power from 400 to 500 horsepower, and they have a reputation for reliability. This generation was the last without emission control devices.
If you need to make common rail repairs, the components are relatively expensive. And if your truck has traveled 200,000 miles without repair or replacement, you’ll need to replace the pump and CP3 pump. The automatic transmission, while doing the job of the factory, doesn’t account for the added power of the modified engines. While all third generation Ram years are desirable, enthusiasts prefer the years 2006 to 2007.
Fourth Generation 2007 to 2019 6.7-litre Ram Cummins Diesel
In mid-2007, Ram began offering a new Cummins diesel engine, this one a 6.7-liter. Every year there were small changes that increased horsepower and torque. By 2010, the 6.7-liter had 370 horsepower, 800 ft-lbs of torque and a towing capacity of 17,500 lbs. By 2011, Ram added its new integrated exhaust brake, which allowed for more pulling power.
Variable geometry turbocharger was used for the first time. There is much less lag and they have better response across the power bands. In mid-2007, emission controls began to appear, including exhaust gas recirculation, diesel oxidation catalytic converter and diesel particulate filters. This was also the era when Ram stepped up its technology with features such as keyless ignition, air suspension and improved infotainment systems.
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