2021 Ram 3500 Factory Maintenance Schedule

Quick reference

Mileage	Service	Notes
5,000	Oil and filter, Tire rotation	Or every 6 months, whichever comes first. Refer to owner's manual for oil type based on engine (gas or diesel).
10,000	Oil and filter, Tire rotation	Or every 6 months.
15,000	Oil and filter, Tire rotation, Cabin air filter replacement, Engine air filter replacement, Fuel filter replacement (diesel)	Or every 12 months for filters. Inspect brake components. Fuel filter is for diesel engines only.
20,000	Oil and filter, Tire rotation	Or every 6 months.
25,000	Oil and filter, Tire rotation	Or every 6 months.
30,000	Oil and filter, Tire rotation, Cabin air filter replacement, Engine air filter replacement, Fuel filter replacement (diesel), Differential fluid inspection/service, Transfer case fluid inspection/service	Or every 12 months for filters. Inspect brake components. Fuel filter for diesel engines only. Refer to owner's manual for specific differential and transfer case service intervals based on usage.
40,000	Oil and filter, Tire rotation	Or every 6 months.
45,000	Oil and filter, Tire rotation, Cabin air filter replacement, Engine air filter replacement, Fuel filter replacement (diesel)	Or every 12 months for filters. Inspect brake components. Fuel filter for diesel engines only.
50,000	Oil and filter, Tire rotation	Or every 6 months.
60,000	Oil and filter, Tire rotation, Cabin air filter replacement, Engine air filter replacement, Fuel filter replacement (diesel), Spark plugs (Hemi gas engine), Transmission fluid and filter (gas & diesel, severe duty/towing), Brake fluid flush	Or every 12 months for filters. Inspect brake components. Fuel filter for diesel engines only. Spark plugs are for the 6.4L HEMI gas engine. Transmission service varies greatly with usage - refer to owner's manual for specifics (especially towing/severe duty). Brake fluid flush recommended every 2-3 years regardless of mileage.
65,000	Oil and filter, Tire rotation	Or every 6 months.
70,000	Oil and filter, Tire rotation	Or every 6 months.
75,000	Oil and filter, Tire rotation, Cabin air filter replacement, Engine air filter replacement, Fuel filter replacement (diesel)	Or every 12 months for filters. Inspect brake components. Fuel filter for diesel engines only.
80,000	Oil and filter, Tire rotation	Or every 6 months.
90,000	Oil and filter, Tire rotation, Cabin air filter replacement, Engine air filter replacement, Fuel filter replacement (diesel), Differential fluid inspection/service, Transfer case fluid inspection/service, Accessory belt inspection/replacement	Or every 12 months for filters. Inspect brake components. Fuel filter for diesel engines only. Inspect accessory belts for wear and replace as needed. Timing chain inspection for both gas and diesel engines.
100,000	Oil and filter, Tire rotation, Cabin air filter replacement, Engine air filter replacement, Fuel filter replacement (diesel), Spark plugs (Hemi gas engine), Coolant flush	Or every 12 months for filters. Inspect brake components. Fuel filter for diesel engines only. Spark plugs are for 6.4L HEMI gas engine. Coolant flush recommended. Timing chain inspection.
105,000	Oil and filter, Tire rotation, Cabin air filter replacement, Engine air filter replacement, Fuel filter replacement (diesel)	Or every 12 months for filters. Inspect brake components. Fuel filter for diesel engines only.
110,000	Oil and filter, Tire rotation	Or every 6 months.
115,000	Oil and filter, Tire rotation, Cabin air filter replacement, Engine air filter replacement, Fuel filter replacement (diesel)	Or every 12 months for filters. Inspect brake components. Fuel filter for diesel engines only.
120,000	Oil and filter, Tire rotation, Cabin air filter replacement, Engine air filter replacement, Fuel filter replacement (diesel), Spark plugs (Hemi gas engine), Transmission fluid and filter (gas & diesel, severe duty/towing), Brake fluid flush	Or every 12 months for filters. Inspect brake components. Fuel filter for diesel engines only. Spark plugs are for the 6.4L HEMI gas engine. Transmission service varies greatly with usage - refer to owner's manual for specifics (especially towing/severe duty). Brake fluid flush recommended every 2-3 years.
130,000	Oil and filter, Tire rotation	Or every 6 months.
140,000	Oil and filter, Tire rotation	Or every 6 months.
150,000	Oil and filter, Tire rotation, Cabin air filter replacement, Engine air filter replacement, Fuel filter replacement (diesel), Differential fluid inspection/service, Transfer case fluid inspection/service, Accessory belt inspection/replacement, Coolant flush	Or every 12 months for filters. Inspect brake components. Fuel filter for diesel engines only. Inspect accessory belts for wear and replace as needed. Coolant flush recommended. Timing chain inspection.

Maintaining your 2021 Ram 3500 according to the factory-recommended schedule is crucial for its longevity, performance, and to uphold your warranty. Ram heavy-duty trucks are built to work, and adherence to these intervals ensures your truck can tackle any task you throw at it. This guide outlines the essential maintenance tasks from 5,000 to 150,000 miles, covering both the 6.4L HEMI gas engine and the 6.7L Cummins Turbo Diesel.

Oil and Filter Changes

For both the gasoline and diesel engines, a regular oil and filter change is the cornerstone of engine health. Ram recommends this service every 5,000 miles or 6 months, whichever comes first, under normal operating conditions. The 6.4L HEMI gas engine typically uses a synthetic blend or full synthetic oil, while the 6.7L Cummins diesel requires a heavy-duty diesel engine oil specifically designed for diesel particulate filter (DPF) equipped engines. Always refer to your owner's manual for the exact oil specification and viscosity. Ignoring regular oil changes can lead to premature engine wear, reduced fuel efficiency, and potentially costly repairs.

Tire Rotation

To ensure even tire wear and extend the life of your tires, a tire rotation is recommended every 5,000 miles along with your oil change. This helps to distribute wear patterns across all four (or six for dually models) tires, promoting better handling and traction. Always check tire pressure after rotation to ensure it aligns with manufacturer specifications, found on the driver's side door jamb.

Air Filters

Both the cabin air filter and the engine air filter are vital for your truck's performance and your comfort. The cabin air filter, which cleans the air entering the passenger compartment, should be replaced every 15,000 miles or 12 months. A clogged cabin filter can reduce airflow from the HVAC system and introduce allergens and dust into the cab. The engine air filter, crucial for engine breathing and preventing contaminants from entering the engine, should also be replaced every 15,000 miles or 12 months. Under dusty conditions, these intervals should be shortened.

Fuel Filter (Diesel Engines Only)

For 2021 Ram 3500s equipped with the 6.7L Cummins Turbo Diesel, the fuel filter is a critical component for protecting your advanced fuel injection system from contaminants. Ram recommends replacing the fuel filter (and often there are two: a primary and a secondary) every 15,000 miles or 12 months. Neglecting this service can lead to reduced fuel flow, decreased engine performance, and very expensive fuel system repairs. It's a crucial part of diesel maintenance.

Spark Plugs (6.4L HEMI Gas Engine Only)

For the 6.4L HEMI gas engine, spark plugs are designed for long life, but still require eventual replacement. Ram recommends replacing the spark plugs every 60,000 miles. While the Cummins uses glow plugs for cold starting, they do not have a regularly scheduled replacement interval like spark plugs and are typically replaced only if they fail.

Timing Belt or Chain

The 2021 Ram 3500, whether equipped with the 6.4L HEMI gas engine or the 6.7L Cummins diesel, utilizes a timing chain rather than a timing belt. Timing chains are designed to last the life of the engine under normal operating conditions and generally do not have a specified replacement interval. However, it's wise to have the timing chain and related components inspected at higher mileage intervals, such as around 90,000-100,000 miles, for any signs of wear or stretch, particularly if any abnormal engine noises are present.

Transmission Fluid Service

The transmission is a critical (and expensive) component of your Ram 3500. For normal duty, Ram does not specify a strict mileage interval for transmission fluid and filter changes, but rather recommends inspection with service as needed. However, for severe duty conditions, such as frequent towing, heavy hauling, or off-road use, Ram advises a transmission fluid and filter service every 60,000 miles. This applies to both the automatic transmissions paired with the gas and diesel engines. Always use the specified Mopar transmission fluid for your particular transmission.

Coolant Flush

To maintain optimal engine cooling and prevent corrosion within the cooling system, a coolant flush is recommended. For the 2021 Ram 3500, Ram suggests flushing and replacing the coolant every 100,000 miles or 5 years, whichever comes first. Always use the Mopar-specified OAT (Organic Acid Technology) coolant.

Brake Fluid Flush

Brake fluid is hygroscopic, meaning it absorbs moisture over time, which can lead to a spongy pedal feel and reduced braking performance. A brake fluid flush is generally recommended every 2-3 years, regardless of mileage, or around 60,000 miles as a rough guideline if considering mileage. This helps to maintain optimal braking performance and prevent corrosion in the brake system.

Differential and Transfer Case Service

These components are essential for delivering power to the wheels, especially for a 4x4 Heavy Duty truck. Ram recommends inspecting differential and transfer case fluid levels at regular intervals. For normal duty, if no issues are noted, replacement might not be specified. However, for severe duty conditions (towing, commercial use, off-roading), consider servicing the differential (front and rear) and transfer case fluids every 30,000 miles. Consult your owner's manual for the specific fluid types and capacities for your truck.

Accessory Belt

The accessory belt (or serpentine belt) drives components like the alternator, power steering pump, and air conditioning compressor. While there isn't a strict replacement interval, it should be visually inspected for cracks, fraying, or wear at every oil change. A good general guideline for replacement is around 90,000 to 100,000 miles, or sooner if signs of wear are evident. A failing accessory belt can leave you stranded.

Severe-duty schedule

Ram heavy-duty trucks are often used in conditions that fall under the "severe-duty" category. If your 2021 Ram 3500 experiences any of the following, you should adhere to a more aggressive maintenance schedule:

• Frequent towing or hauling heavy loads: Shorten oil change intervals, inspect brakes more often, and service transmission/differentials/transfer case more frequently.
• Driving in dusty, sandy, or muddy conditions: Replace engine and cabin air filters, and diesel fuel filters, more often. Consider more frequent oil changes due to increased particulate contamination.
• Extended idling or short trips (under 10 miles) in cold weather: These conditions can prevent the engine from reaching optimal operating temperature and lead to condensation buildup in the oil, necessitating more frequent oil changes.
• Extreme hot or cold climates: Can accelerate the degradation of fluids and rubber components. Follow severe-duty intervals for fluids.
• Off-road operation: More frequent inspection of chassis components, suspension, and driveline fluids.

In general, for severe duty, consider shortening oil and filter changes to every 3,000-4,000 miles. Replace air and fuel filters more frequently (every 7,500-10,000 miles). Transmission, differential, and transfer case fluid changes should be done every 30,000-60,000 miles.

Known issues by mileage

The 2021 Ram 3500 is part of the fifth generation Ram HD, which generally enjoys a reputation for robustness. However, some common areas to watch for, based on similar models and generations, include:

• 30,000-60,000 miles:
  • Diesel Exhaust Fluid (DEF) system issues: While often covered under warranty, DEF system sensor failures or crystallization can lead to "limp mode" and require dealer diagnostics.
  • Brake wear: Heavy-duty use, especially towing, can lead to accelerated wear of brake pads and rotors.
  • Suspension components: Given the weight and work capabilities, ball joints, tie rod ends, and other steering/suspension components may begin to show wear.
• 60,000-100,000 miles:
  • Turbocharger issues (Cummins): Though generally reliable, some owners might experience turbo wear or issues, often signaled by unusual noises or decreased power.
  • Transmission issues: While robust, heavy towing without proper fluid changes can lead to premature wear or shift quality issues.
  • DPF regeneration issues (Cummins): Over time, DPFs can become clogged, requiring more frequent or extended regeneration cycles, or even manual cleaning/replacement.
• 100,000+ miles:
  • Injection system wear (Cummins): High-pressure fuel pump (HPFP) and injector wear can begin to manifest at higher mileages, though modern Cummins engines are very durable.
  • Accessory belt component wear: Idler pulleys, tensioners, and the accessory belt itself should be thoroughly inspected as these components age.
  • Steering gearbox play: Some heavy-duty trucks can develop minor play in the steering gearbox at higher mileages.

Regular maintenance and proactive inspections can help identify and address these potential issues before they become major problems.

Estimated cost per service

The cost of maintenance for your 2021 Ram 3500 will vary significantly based on your location, the shop you choose (independent vs. dealership), and whether you opt for OEM parts. Here's a general estimate:

• Oil Change (Gas): $80 - $150 (depending on synthetic type and shop rates)
• Oil Change (Diesel): $150 - $300 (higher volume of specialized oil, two filters)
• Tire Rotation: $25 - $50 (often included with oil change at dealerships)
• Cabin Air Filter Replacement: $50 - $100 (part and labor)
• Engine Air Filter Replacement: $60 - $120 (part and labor)
• Fuel Filter Replacement (Diesel): $150 - $300 (includes parts for multiple filters and labor)
• Spark Plug Replacement (Hemi): $300 - $600 (includes parts for 16 plugs and labor)
• Transmission Fluid Service (Gas/Diesel): $300 - $700+ (depending on pan drop/filter replacement and fluid type)
• Coolant Flush: $200 - $400
• Brake Fluid Flush: $150 - $250
• Differential Service (per axle): $100 - $200
• Transfer Case Service: $100 - $200
• Accessory Belt Replacement: $150 - $300 (belt and labor, possibly tensioner/idler pulleys if needed)

These are estimates, and getting quotes from several reputable shops is always recommended.

What you can DIY vs shop

Many maintenance tasks on your 2021 Ram 3500 are within the capabilities of a competent DIYer, potentially saving you money. However, some jobs are best left to a professional, especially considering the size and complexity of a heavy-duty truck.

DIY-Friendly Tasks:

• Oil and Filter Changes (Gas): Fairly straightforward with the right tools and disposal methods for used oil.
• Oil and Filter Changes (Diesel): More involved due to larger volumes and multiple filters, but still feasible for experienced DIYers.
• Tire Rotation: Requires a good jack and jack stands, or a lift. Dually models are more challenging.
• Cabin Air Filter Replacement: Usually very easy, located behind the glove box.
• Engine Air Filter Replacement: Typically a simple process of opening the airbox and swapping filters.
• Wiper Blade Replacement: A simple, quick task.
• Fluid Level Checks: Regularly checking coolant, brake fluid, power steering fluid, and washer fluid is easy and important.

Best Left to a Professional Shop:

• Fuel Filter Replacement (Diesel): Can be messy, involve bleeding the fuel system, and proper priming is critical to avoid damage to the injection pump. Given the cost of diesel fuel system components, it's often safer to have a pro do it.
• Spark Plug Replacement (Hemi): With 16 plugs, often recessed and requiring specific torque, this can be time-consuming and challenging for some. Mis-torqued plugs can cause issues.
• Transmission Fluid Service: Requires specific fluid types, often pan removal, filter replacement, and ensuring correct fluid level, which can involve specific temperature checks. This is a critical system.
• Coolant Flush: Involves draining, flushing, and refilling with the correct concentration of specialized coolant. Proper bleeding of air from the system is paramount.
• Brake Fluid Flush: Requires specialized tools to properly bleed the brake system and ensure no air is introduced. Critical for safety.
• Differential and Transfer Case Service: Involves specific gear oil weights, proper gasket sealing, and often working in tight spaces underneath the truck.
• Accessory Belt Replacement (if complicated routing or seized components): While a basic belt swap can be DIY, if tensioners or idlers are seized, specialty tools or expertise might be needed.
• Any diagnostic work: If you hear an unusual noise or have a warning light, professional diagnostics can save you time and money by pinpointing the issue accurately.

Always consider your comfort level, available tools, and the potential risks involved before attempting any maintenance. When in doubt, trust your Ram 3500 to certified technicians.

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