One of the most important service items is using the correct transmission fluid. This guide explains the correct transmission fluid type for the 6.7 Cummins and highlights five of the best compatible fluids.
6.7 Cummins Transmission Fluid Type
1. Mopar ATF+4 Automatic Transmission Fluid
Features:
- Factory-recommended fluid for 68RFE transmissions
- Full synthetic formulation
- Designed specifically for Chrysler and RAM vehicles
- Excellent oxidation and wear resistance
- Maintains smooth shift performance under heavy loads
This fluid is the safest choice for owners who want to follow the manufacturer’s specifications exactly.
2. Valvoline ATF+4 Full Synthetic Automatic Transmission Fluid
Features:
- Meets and exceeds ATF+4 specifications
- Full synthetic for high-temperature stability
- Provides excellent clutch protection
- Reduces transmission wear and friction breakdown
- Suitable for heavy-duty towing applications
Valvoline ATF+4 is a trusted aftermarket alternative that performs similarly to OEM fluid.
3. Doc’s Diesel ATF+4 Full Synthetic Transmission Fluid Kit
Features:
- Designed for 6.7 Cummins trucks with 68RFE transmissions
- Includes full synthetic ATF+4 fluid
- Often bundled with transmission filters for full service
- Improves shift quality and transmission response
- Ideal for DIY transmission servicing
This option is convenient for owners performing complete fluid and filter changes.
Related Transmission Fluid Weight(For ALL Fluid Types)
4. Aisin Transmission Fluid (JWS 3309 Specification)
Features:
- Designed for Aisin AS68RC and AS69RC transmissions
- Meets JWS 3309 and ATF T-IV requirements
- Provides stable friction control
- Protects against overheating and clutch slippage
- Ensures long-term durability under heavy loads
This fluid is the correct choice for trucks equipped with Aisin automatic transmissions.
5. Valvoline MaxLife Multi-Vehicle Automatic Transmission Fluid
Features:
- Compatible with JWS 3309 applications
- Full synthetic blend for extended fluid life
- Helps maintain smooth shifting
- Provides strong wear and oxidation protection
- Suitable for high-mileage and heavy-duty use
Always confirm compatibility with your specific transmission before using multi-vehicle fluids.
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Understanding 6.7 Cummins Transmission Options
The 6.7 Cummins engine has been paired with two primary automatic transmissions:
- 68RFE Automatic Transmission
- Aisin AS68RC and AS69RC Automatic Transmissions
Each transmission requires a specific fluid type designed to meet its friction, hydraulic, and thermal demands. Using the incorrect fluid can lead to poor shifting, overheating, clutch wear, and premature transmission failure.
Recommended Transmission Fluid Type
68RFE Transmission
The 68RFE automatic transmission requires ATF+4 specification fluid. This is a full synthetic automatic transmission fluid developed specifically for Chrysler, Dodge, and RAM vehicles. ATF+4 provides proper friction characteristics, excellent heat resistance, and protection against oxidation.
Aisin AS68RC / AS69RC Transmission
Aisin transmissions used behind the 6.7 Cummins require fluid that meets JWS 3309 / ATF T-IV–type specifications. These fluids are formulated differently from ATF+4 and are not interchangeable. Always verify which transmission your truck has before servicing.
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Transmission Fluid Capacity Overview
Approximate fluid capacities vary by transmission type:
- 68RFE: 16 to 18 quarts (including torque converter)
- Aisin AS69RC: 17 to 19 quarts (including torque converter)
A standard drain-and-refill typically replaces only part of the total capacity. Complete fluid exchange requires additional procedures.
Recommended Service Intervals
- Normal driving: Every 60,000 miles
- Severe use or towing: Every 30,000 to 40,000 miles
Regular fluid changes help prevent overheating, slipping, and premature wear, especially for trucks used for towing or commercial work.
FAQs
What kind of transmission fluid does a 68RFE take?
The 68RFE automatic transmission used behind the 6.7 Cummins requires ATF+4 automatic transmission fluid. ATF+4 is a full synthetic fluid specifically formulated for Chrysler, Dodge, and RAM transmissions. Using any other type of fluid can cause improper shifting, overheating, and accelerated clutch wear.
How much transmission fluid does a 6.7 Cummins take?
Transmission fluid capacity depends on the transmission type. A 6.7 Cummins with a 68RFE transmission typically holds 16 to 18 quarts when completely dry, including the torque converter. Trucks equipped with an Aisin AS69RC transmission usually require 17 to 19 quarts. A standard drain and refill will replace less than the full capacity.
What kind of transmission fluid does a Dodge Ram 3500 take?
A Dodge RAM 3500 with a 6.7 Cummins uses ATF+4 if it is equipped with the 68RFE transmission. If the truck has an Aisin AS68RC or AS69RC transmission, it requires a fluid that meets JWS 3309 or ATF T-IV specifications. Always confirm the transmission type before adding fluid.
What type of transmission fluid does a 2012 6.7 take?
A 2012 6.7 Cummins equipped with the 68RFE transmission requires ATF+4 transmission fluid. Some 2012 RAM 3500 models may be equipped with an Aisin transmission, which uses JWS 3309–spec fluid. Checking the transmission tag or build sheet is recommended to confirm the correct fluid type.
Can I use ATF instead of ATF +4?
No, standard or generic ATF should not be used in place of ATF+4. ATF+4 has specific friction and viscosity properties required for the proper operation of Chrysler and RAM transmissions. Using non-ATF+4 fluid can cause harsh shifting, torque converter shudder, overheating, and premature transmission failure.
What transmission is better, Aisin or 68RFE?
Neither transmission is universally better; each serves a different purpose. The Aisin transmission is designed for heavy-duty towing and commercial use, offering stronger internals and higher torque capacity. The 68RFE transmission is better suited for daily driving and moderate towing, with smoother shifting and lower service costs. The best option depends on how the truck is used rather than overall superiority.
Final Thoughts
Using the correct transmission fluid for your 6.7 Cummins truck is essential for reliability, performance, and long service life. The 68RFE transmission requires ATF+4 fluid, while Aisin transmissions require JWS 3309–spec fluid. Choosing a high-quality, specification-approved transmission fluid and maintaining proper service intervals will protect your investment and keep your truck performing at its best.
