In the late 1980s, Chrysler’s line of heavy-duty pickups was the equivalent of controlled decay. The loss of big-block gasoline V8 options, the discontinuation of crew cab configurations, an exterior virtually unchanged since 1972, and an aging overall platform painted a picture of a life support product. Fortunately, a few good men convinced Chrysler’s top buyers that a diesel engine option would not only sell, but make the brand competitive again. After winning a contract with Cummins, a global engine supplier that also dominated the American Class 8 truck scene, a diesel-powered Ram followed soon after.
The public ate them up, and a limited supply of 16,750 Cummins-powered Rams were sold for the ’89 model year. Ultimately, Chrysler had to stop taking orders for Cummins-equipped trucks until it could resupply in 1990 and ramp up production efforts. ? We’ll cover it all below, from axles to transmissions to brakes and suspension. In terms of towing, payload and fuel efficiency, these trucks have changed the game forever. In the near future, we will continue this article with a full examination of the ’94 Ram 2500 and 3500s – trucks that once again revolutionized the heavy-duty pickup segment.
5.9L Cummins: the engine of the Redeemer
The 5.9L Cummins turbodiesel has been called the engine that saved Dodge trucks. And while that statement may be up for debate as it pertains to half-tons, it’s certainly true for the automaker’s ¾-ton and larger trucks. With instant name recognition, the only turbocharged diesel engine in its class, the only direct injection diesel candidate in its class, and the most torque in the segment (in addition to offering the most horsepower per cubic inch in a diesel), the name was Cummins a giant selling point – even though it was packaged in the same basic chassis Chrysler had been using since 1972. The Cummins diesel option also came with Dodge’s 7-year/100,000 mile warranty. It had a modest 160 horsepower at 2,500 rpm, but produced a class-leading 400 lb-ft of torque at 1,700 rpm.
The last ride of an outdated platform
Aside from twin rectangular headlights, wraparound taillights, and those signature square body lines, the ’89-’93 trucks were essentially nothing more than facelifted versions of the ’72 D-Series pickups. Despite this, the aging platform was made to work and the carbon steel frame (with seven cross-members for structural reinforcement) was able to withstand the torque of the Cummins. And many forget that Dodge offered a “fully welded” cargo bed design on these trucks, where the cargo bed was free of exposed bolts, unlike the competition, where trapped water would often lead to rust.
Conventional leaf spring suspension
A solid leaf-sprung front axle was the order of the day at this time and Chrysler had no intention of reinventing the wheel in this area. Naturally, independent front suspension was used on the two-wheel drive D250 and D350 models. All models used leaf spring rear suspension, which came with different spring rates depending on the specific configuration. On cab and chassis trucks, a larger leaf stack could increase the vehicle’s payload to as much as 6,270 pounds.
Dana axles and front disc brakes
Under the rear leaf springs, the ’89-’93 Dodges packed a Dana 70 axle. The Dana 70 had a 10.54-inch diameter ring gear and a shaft ratio of 3.55:1 or (less commonly) 3.07:1 when equipped with an automatic transmission, and 4.10:1 with an manual gearbox. The Dana 70 also featured a maximum allowable axle weight (GAWR) of up to 5,500 pounds on ¾-ton models and 6,200 pounds on 1-ton models. Four-wheel drive models featured a 9.75-inch diameter Dana 60 sprocket with 12.82-inch x 1.25-inch brake discs. Rear drum brakes were used (12×2.5 in), with the braking system being vacuum assisted. From 1990 anti-lock brakes on the rear wheels were implemented as standard equipment.
A Little Transfer Case Love
Transfer cases are nowhere near getting the appreciation they deserve. These power transmission devices are incredibly strong and often survive the life of a truck eaten by a handful of transmissions. In the case of the first generation Cummins, 4×4 versions were all treated to an NP205 married to the transmission. The cast-iron, gear-driven transfer case was widely used in GMs and is still widely respected in the off-road world. For diesel-equipped versions of ’89-’93 Dodge trucks, the NP205 benefited from a 29-spline input shaft, while gas versions retained the 23-spline shaft used since 1980.
While later years of Cummins powered Rams called for a detuned version of the 5.9L diesel behind the automatic transmission option, this was not the case from ’89-’93. The three-speed TorqueFlite A-727 gained attention from ’89-’91, while the four-speed overdrive A518 (later renamed the 46RH) took over midway through the ’91 model year. For ’93, a $375 dealer-installed “super duty” transmission cooler option became available to automatic truck owners, increasing the maximum trailer towing capacity from 12,000 pounds GCW to 14,000 pounds GCW. A Getrag G360 manual transmission mated to a 13-inch clutch was also available during the production run of the first-generation Cummins.
“The Hardest Working Pickup in America”
With the addition of the 5.9L Cummins, Dodge was very formidable in the towing segment. In fact, a standard 1993 cab, 4×2 D250 or single rear wheel D350 spec’d with the Cummins, the Getrag manual transmission and a 4.10 axle ratio, had a gross combined weight (GCWR) of 17,000 pounds (the 5.9L petrol version was valued at £13,500). Max trailer weight checked in at 11,900 lbs. Last year (’93), a Cummins-powered Dodge even won the “Towing Vehicle of the Year” award from the now-defunct Trailer Boats magazine. Payload was also competitive, with a well-specified two-wheel-drive D250 able to carry 4,305 pounds and a dual-rear-wheel D350 able to carry 5,480 pounds.
Curb that never fades
Despite all the modern luxuries available in last-model Ram trucks—along with the 1,000-lb-ft powertrains and 40,000-pound GCWR chassis—first-generation Rams still get the attention of a great many purists. In Chris Ohl’s case, he technically didn’t even start with a first-generation Cummins, but rather transformed this ’82 crew cab into a breathtaking Cummins-powered 5.9-liter gooseneck farm truck. Dodge die-hards will note that the first-generation Cummins was never offered in four-door configurations… The Chris’ crew cab interior is adorned with fourth-generation leather seats, front and rear, as well as a ’17 model year center to console. His D350 is proof that the classic first-generation look is still sought after by truck enthusiasts decades after the last one rolled off the assembly line.
More of Driving line
- For an in-depth look at the parts and components that made the 5.9L Cummins so rugged, take a step back in time with us here.