2021 Ram Heavy Duty Available Performance Features

2021 Ram HD Cumming Turbo Diesel Engine



  • Available on 2500 and 3500 models
  • 410 hp
  • 429 lb-ft of torque
  • Fuel Saver Technology
  • Matched with the 8HP75-LCV electronically controlled 8-speed automatic transmission
  • Active Noise Control System on all applications, except Regular Cab

Big HEMI® V8 power when maximum confidence is the only way to roll!

Eight-Speed Automatic Transmission

The robust and advanced-design ZF 8HP75-LCV 8-speed automatic is paired with the 6.4L HEMI V8.

To handle the increased towing and payload capacities, upgrades include:

  • Additional torque-converter brazing
  • Two gear sets with additional pinion gears
  • Heavy-duty PARK system

Smooth and reliable, the 8HP75-LCV offers a level of shift refinement not usually seen in Heavy Duty trucks:

  • Fully electronic operation
  • Innovative and convenient rotary E-shifter
  • On-the-fly shift mapping with more than 40 individual maps to optimize shift quality/points regardless of load or conditions

68RFE Six-Speed Automatic Transmission

Smooth Confidence!

Ram Heavy Duty non-high-output diesel powered models feature the 68RFE electronically controlled six-speed transmission:

  • Specifically engineered for the 6.7L Cummins Turbo Diesel engine to offer surprising acceleration in addition to extra efficiency
  • Shift quality has been enhanced using a variable-force solenoid for torque converter clutch engagement AND a unique reverse accululator

Auto Level Rear Air Suspension

Add the available auto level rear air suspension to the Ram 2500 and 3500 for improved ride quality and control unloaded, loaded or anywhere in between!

Air springs:

  • Inflate/deflate to maintain rear ride height (load-leveling)
  • Work to maintain suspension and driveline geometry
  • Help aid control and confidence on the road

Three selectable ride height levels controlled via a switch on the console:

  • In the Normal Load Leveling mode (Default), the system continually monitors ride heights on both sides of the vehicle and adjusts accordingly in case of load shift or changes in road surface.
  • In the Alternate Ride Hight mode (towing), the system lowers the rear suspension approximately on inch for more level alignment between the hitch and trailer tongue.
  • Bed Lowering mode (Trailer hook-up, cargo loading), the system lowers the bed to aid trailer hitch hook-up or reduce lifting height when loading up the bed.




 Electric-Shift Part-Time Transfer Case

Shift-on-the-fly convenience for transitions from road to job site!

Ram Heavy Duty 4×4 models offer an available part-time four-wheel-drive system with electric-shift control:

  • A simple button push changes Ram from two- to four-wheel-drive high or low
  • This system is intended to be driven in two-wheel drive for normal street and highway conditions
  • When additional traction is required on slippery or loose surfaces, such as snow, mud or sand, this system provides the convenience and peace of mind of available shift-on-the-fly four-wheel-drive capability
  • When four-wheel drive is not necessary, a front axle disconnect system disengages the front drive axle to help reduce parasitic losses and, thereby, help improve fuel efficiency.

The part-time transfer case provides three operating ranges plus a neutral position:

  • 2WD High
  • 4WD Lock
  • 4WD Low

It can be shifted into 4WD Lock on the fly at speeds up to 55 mph


Clean, efficient, dependable and durable, the proven 6.7L Cummins Turbo Diesel engine:

  • Produces 370 hp and 850 lb-ft of torque and is mated with the 68RFE 6-speed automatic transmission (available on 2500/3500)
  • Cummins 6.7L High-Output Turbo Diesel version produces 420 hp and best-in-class1 1,075 lb-ft of torque and is mated with the AISIN 6-speed heavy-duty automatic transmission (available on 3500 only)

Supports impressive capabilities:

  • Maximum Gross Combined Weight Rating (3500) = 45,000 lb2
  • Maximum Gross Vehicle Weight Rating (3500) = 14,000 lb2
  • Best-in-class1 Maximum Diesel Towing Rating (3500) = 37,100 lb2
  • Maximum Payload Rating (3500) = 6,840 lb2

The Ram Brand applies SAE J2807 testing criteria to its entire pickup truck line and towing claims


  • The compacted graphite iron block helps provide reduced weight and minimized noise/vibration/harshness (NVH)
  • The cooling system achieves heat reduction via a “low-slung” positioned charge air cooler, faster-sequenced water pumps, an efficient 11-blade radiator fan and a dual radiator system
  • The “smart” exhaust brake is an enhanced design for smoother, less aggressive exhaust braking characteristics, contributing to improved driver control, reduced brake fade and longer brake life
  • To reduce operating costs, diesel oil change intervals are as high as a best-in-class1 15,000 miles
  • 5-year/100,000-Mile Diesel Powertrain Limited Warranty3 protects your investment and promotes on-the-job confidence by covering the cost of parts and labor

Power, efficiency and confidence with the legendary Cummins diesel!


Your diesel engine will sound, feel, drive and operate differently from a gasoline-powered engine

The Cummins diesel engine in your new vehicle provides good operating efficiency rugged durability and high torque for pulling heavy loads:

  • Meets all EPA heavy-duty diesel engine emission standards
  • Equipped with a state-of-the-art engine and exhaust system
  • These systems are seamlessly integrated into your vehicle and managed by the Cummins Powertrain Control Module (PCM)
  • The PCM manages engine combustion to allow the exhaust system’s catalyst to trap and burn particulate matter (PM) pollutants (see your owner’s information for details)
  • Ability to alert you to important messages that will be displayed in your instrument cluster display


The diesel engine uses a Diesel Exhaust Fluid (DEF) system to help produce cleaner emissions:

  • A gauge displays the Diesel Exhaust Fluid level and a warning light will activate any time the level gets too low
  • The DEF fluid cap is located in the fuel filler door

To add DEF fluid to your vehicle:

  • Remove the cap from the DEF tank
  • Insert the DEF fill nozzle into the DEF tank filler neck
  • Stop filling the DEF tank immediately if DEF stops flowing from the fill bottle into the DEF tank, DEF splashes out of the filler neck or the DEF pump nozzle automatically shuts off
  • Reinstall the cap onto the DEF tank

Be sure to keep diesel fuel and diesel exhaust fluid separate:

  • A small amount of DEF in the diesel fuel tank can result in severe damage in the engine, fuel pump and injectors
  • If this happens, do not start the engine
  • Contact an authorized dealer
  • Never let anything other than diesel exhaust fluid into the DEF tank. (This may result in the need to replace the entire DEF system)
  • Always use separate containers, funnels and nozzles for fuel and DEF


The Water-In-Fuel indicator light will illuminate when there is water detected in the fuel water separator filters:

  • If this light remains on, do not start the vehicle before you drain the water from the fuel water separator filters
  • If water is detected in the fuel water separator filters while the engine is running, or while the key is in the On/Run position, the indicator light will illuminate and an audible chime will be heard five times
  • At this point, you should stop the engine and drain the water from the fuel water separators

There are two fuel filter assemblies

One is located on the driver’s side of the engine:

  • The best access to this water drain valve is from under the hood

The second one is on the underbody, located in front of the rear axle above the drive shaft:

  • The best access to this water drain valve is from under the vehicle

To drain the fuel water separator filters when the Water-In-Fuel indicator light is on:

  • Within 10 minutes of turning the engine off, turn the engine-mounted filter drain valve located on the side of the filter housing, counterclockwise 1/4 turn to drain water that may have accumulated
  • Turn the underbody-mounted filter drain valve, located on the bottom of the filter housing, counterclockwise one full turn to drain water that may have accumulated in this filter
  • You’ll need to turn the ignition switch to the On/Run position and allow any accumulated water to drain
  • Leave the drain valve open until all water and contaminants have been removed
  • When clean fuel is visible, close the drain valve by turning it clockwise until you feel resistance
  • Then, turn the valve an additional ½ turn to properly compress the seal
  • Do not over-compress the seal. Do not use tools.
  • Turn the ignition to Off


In cold weather (engine temperatures below 66° F, 19° C), the Wait-To-Start light will remain on, indicating the intake manifold heater system is active:

  • If this is the case, starting the 6.7L diesel engine is a bit different than usual
  • If the Wait-To-Start light is on, pushing the Engine Start button, with the driver’s foot on the brake, will move the ignition from Off or ACC to Run, but the engine will not immediately crank (this is normal)
  • The Wait-To-Start light will remain on for a period of time while the manifold heater system preheats the engine
  • During this time, the instrument cluster will display a gauge or bar that will indicate the wait-to-start time period until engine start
  • When the engine Wait-To-Start light goes off, the engine will automatically crank
  • After engine startup, check to see that there is oil pressure

Adaptive Steering System

The available Adaptive Steering System can take inputs from road and vehicle conditions and adapt steering feel to help improve the driver experience.

  • Adapt steering feel based on vehicle speed
  • Compensate for road crown
  • Assist driver in returning wheel to center


Manual-Shift Part-Time Transfer Case

Shift-on-the-fly convenience for transitions form road to unpaved situations!

Ram Heavy Duty 4×4 Tradesman and Power Wagon models offer a manual-shift transfer case to engage the part-time four-wheel-drive system:

  • Moving the floor-mounted lever changes Ram from two to four-wheel drive high or low.
  • This system is intended to be driven in two-wheel drive for normal street and highway conditions.
  • When additional traction is required on slippery or loose surfaces, the system provides four-wheel-drive capability.
  • When four-wheel drive is not necessary, a front axle disconnect system disengages thte front drive axle to help reduce parasitic losses and, thereby, help improve fuel efficiency.

The part-time transfer case provides three operating ranges plus a neutral position:

  • 2WD High
  • 4WD Lock
  • 4WD Low
  • Neutral

It can be shifted into 4WD Lock on the fly at speeds up to 55 mph

6,000-lb Front Solid Axle with Coil Springs

  • All Ram HD models feature a 3-link solid front axle with coil springs for increased capacity
  • Handling nd hauling performance geared for severe off-road work conditions
  • Enhances ride quality for a comfortable and quiet on-road ride


Protection Group

2021-ram-heavy-duty-protection group

On 4×4 models (except Power Wagon), the available Protection Group helps aid confidence in rugged situations:

  • Tow hooks (Only 2500 models, except Limited)
  • Transfer case skid plate shield

An excellent choice if work can take you off the beaten path!

3.73 Rear Axle Ratio

The 3.73 rear axle ratio provides a balance of operating efficiency and towing capability

4.10 Rear Axle Ratio

The available 4.10 rear axle ratio provides superior towing capability on Ram 2500 and 3500 models

Antispin Rear Differential

The antispin rear differential provides additional traction capability over a conventional open rear differential to aid hauling and driving confidence on slippery surfaces:

  • Available on 2500 models
  • Available on 3500 models

Electronic Range Select

Increased confidence and convenience when hauling!

Electronic Range Select helps prevent hunting between gears by allowing you to limite the highest available gear:

  • Manually upshift or downshift for more precise control of the vehicle, which is especially useful when towing
  • Featured on all Ram automatic transmissions




Hill Descent Control

Available on all 2500 Crew Cab and Mega 4×4 models and standard on Ram Power Wagon, Hill Descent Control maintains vehicle speed while descending hills during off-road driving situations:

  • The system applies brake pressure as needed to descend a grade at a fixed speed
  • With the vehicle in 4LOW, push the Hill Descent Control button located on the switch bank
  • The Driver Information Display in the center of the cluster will identify that system is active
  • Once put in Drive, the system defaults to the slowest speed, 0.6 mpg
  • Speed can be changed with the +/- ERS button on the shifter
  • There are nine speed settings between 0.6 and 5.6 mpg
  • The speed settings are displayed to the right of the transmission gear indicator
  • Pushing the Hill Descent Control button again will turn the system off

Hill Descent Control is only intended for low-speed off road driving:

  • A flashing “Hill Descent Control” indicator identifies that the brakes are getting too hot and the vehicle should be stopped to allow the brakes to cool.

Hill Descent Control helps provide an extra measure of security and control!

Hill Start Assist

Hill Start Assist system assists the driver when starting vehicle from stopped position on hill:

  • Maintains brake pressure for short time after driver takes foot off brake pedal
  • If driver does not apply throttle during this period, system releases brake pressure, and vehicle will begin to roll downhill
  • System releases brake pressure in proportion to the amount of throttle applied as the vehicle starts to move

Criteria must be met for Hill Start Assist to activate:

  • Vehicle must be stopped
  • Vehicle must recognize position on a grade (at least 5% to 8%, depending on model)
  • Gear selection matches vehicle uphill direction

Hill Start Assist works in REVERSE and all forward gears when criteria are met:

  • Will not activate if vehicle is in NEUTRAL or PARK

Tow/Haul Mode

Increased confidence and convenience when hauling!

When the vehicle’s load causes the transmission to hunt between two gears, the driver and select the Tow/Haul mode:

  • Controlled through a switch in the center stack
  • Engages another transmission program designed to assist with towing
  • Delays shifts into higher gear by allowing lower gear to perform at slightly higher speeds
  • Improves vehicle performance and contributes to optimal fuel efficiency by eliminating the hunting between gears.

Trailer Brake Controller

Available trailer brake controller provides better driver control in towing situations:

  • Completely integrated into the vehicle’s electrical control system
  • Trailer brake controller information conveniently displayed in the instrument cluster
  • Controlled by a handy switch on the lower switch bank

The trailer brake controller features four settings to match trailer brake control to the towing situation:

  • Light electric
  • Heavy electric
  • Light electric over hydraulic
  • Heavy electric over hydraulic
  • Selectable in Driver Information Display

Gain setting can be:

  • Increased to a maximum of 10
  • Decreased to a minimum of zero (no trailer braking)in increments of 0.5

Adjustments should only be performed in a traffic free environment at speeds of approximately 20-25 mph

Ram Off-Road Pages

Available Off-Road Pages provide:

  • Real time off-road performance data and in-depth diagnostics provide an optimized experience.

Off-road status bar continuous display:

  • Transfer case status
  • GPS coordinates
  • GPS altitude
  • Off-Road +

Greater details found within the information tabs:

  • Drivetrain provides status of front and rear axle lockers, sway bar and transfer case
  • Accessory gauges display coolant temperature, oil temperature, oil pressure, transmission temperature (automatic only) and battery voltage
  • Pitch/Roll displays pitch and roll angles graphically and numerically



Active Grille Shutter System

Active grille shutters help optimize aerodynamics and engine cooling performance:

  • Whether the shutter is open or closed is based on engine coolant temperature and vehicle speed

System will open when the vehicle is:

  • Traveling uphill
  • Pulling a trailer
  • In hot, congested driving

System will close at:

  • Highway speeds (less engine cooling required)
  • When aerodynamic drag most significant