Dodge 5.7L Automatic Transmission(545RFE)

The Dodge 5.7L Automatic Transmission(545RFE), when equipped with the 5.7L HEMI V8 engine and 545RFE automatic transmission, represents a popular configuration favored by truck enthusiasts for its balance of power, towing capability, and relative reliability. This combination was widely used in the mid-2000s through the early 2010s and remains a popular choice in the used truck market and among mechanics and performance tuners.

This document takes a comprehensive look at the mechanical pairing, its performance characteristics, service requirements, known issues, and upgrade potential.

Dodge 5.7L Automatic Transmission(545RFE) Overview

The Dodge 5.7L Automatic Transmission(545RFE) (short for “Hemispherical Combustion Chamber”) engine was introduced in the Dodge Ram in 2003, replacing the older 5.9L Magnum V8. It represented a major leap in engine technology for Chrysler, offering more horsepower and torque with improved efficiency.

Specifications:

• Displacement: 5.7 liters (345 cubic inches)

• Block Material: Cast iron

• Head Material: Aluminum

• Compression Ratio: 9.6:1 (varies slightly by model year)

• Horsepower: ~345 hp @ 5400 RPM

• Torque: ~375 lb-ft @ 4200 RPM

• Fuel System: Sequential Multi-Port Fuel Injection

• Valve Configuration: OHV, 16-valve (2 per cylinder)

Features:

• Coil-on-plug ignition

• Variable cam timing (introduced in later versions)

• MDS (Multi-Displacement System) in some models (cylinder deactivation under light loads)

Dodge 5.7L Automatic Transmission(545RFE) Overview

The Dodge 5.7L Automatic Transmission(545RFE) (Rear-wheel drive Fully Electronic) transmission is an evolution of the earlier 45RFE, which debuted in Jeep models. Chrysler upgraded it in 2001 by adding another overdrive gear and renaming it the 545RFE. Though labeled a 5-speed, the 545RFE uses six internal gears, with the transmission’s control module determining gear shifts.

Key Specs:

• Type: Electronically controlled, 5-speed automatic

• First Gear Ratio: 3.00:1

• Second Gear Ratios: 1.67:1 and 1.50:1 (alternate 2nd gear)

• Third Gear: 1.00:1

• Fourth Gear: 0.75:1 (OD)

• Fifth Gear: 0.67:1 (OD)

• Reverse: 3.00:1

Design Notes:

• Designed for rear-wheel drive and 4WD applications

• Utilizes adaptive shift strategies

• Features dual second-gear ratios for performance/load optimization

• Internal TCM (transmission control module)

• Torque converter with lockup clutch

 Performance and Driving Dynamics

When paired together, the Dodge 5.7L Automatic Transmission(545RFE) provide a responsive, torque-rich driving experience ideal for towing, off-road driving, and highway cruising.

Towing Capacity:

• Dodge Ram 1500 (with 5.7L HEMI and 545RFE): up to 9,000 lbs, depending on axle ratio and cab configuration

Fuel Economy:

• Not exceptional by modern standards, averaging 13–15 MPG city / 17–19 MPG highway (real-world use, depending on load and driving habits)

Shifting Characteristics:

• The 545RFE shifts smoothly under normal driving conditions

• Under load, the alternate 2nd gear (2nd Prime) helps optimize acceleration

• Lock-up torque converter improves efficiency during highway driving

 Common Problems and Issues

Like any transmission, the Dodge 5.7L Automatic Transmission(545RFE) has known issues that can affect long-term reliability. Regular maintenance significantly improves its lifespan, but some factory design elements have limitations.

1. Torque Converter Clutch Failure

• Symptoms: Shuddering during highway cruising, slipping, RPM fluctuations

• Cause: Wear of clutch materials; fluid breakdown

2. Solenoid Pack Malfunction

• Symptoms: Hard shifts, failure to upshift/downshift, fault codes (e.g., P0750 series)

• Solution: Replacement of solenoid pack (located on valve body)

3. Valve Body Wear

• High-mileage trucks may exhibit poor shift quality due to worn valve bores, particularly in the accumulator circuits

4. Delayed Engagement

• Delay when shifting from park to drive/reverse, especially when cold

• Often due to low fluid level or filter sucking air

5. Overheating

• Common under towing conditions without a dedicated transmission cooler

• Can lead to accelerated wear and fluid breakdown

 Maintenance Best Practices

Proper maintenance is the most critical factor in maximizing the life of the 545RFE. Chrysler marketed the transmission as “sealed for life” in some models, but real-world experience shows fluid changes are essential.

Fluid and Filter Changes

• Recommended Interval: Every 30,000–60,000 miles

• Fluid Type: ATF+4 only (do not substitute with Dexron/Mercon)

• Filter Kit: Use Mopar or high-quality aftermarket kits with both sump and cooler filters

Pan Upgrade

• Consider an aluminum deep pan for better cooling and extra capacity (especially for towing)

Cooling System

• Install an auxiliary transmission cooler if towing or operating in hot climates

 Rebuild and Upgrade Paths

For owners looking to rebuild or improve the Dodge 5.7L Automatic Transmission(545RFE) for heavy-duty use, performance upgrades are available.

Common Upgrades:

• Shift kits: Improve shift firmness and reduce wear

• High-performance solenoid packs: More durable under high load

• Aftermarket torque converters: With stronger lockup clutch

• Valve body upgrades: Address cross-leaks and improve shift consistency

• Coolers and thermostatic bypass kits: Maintain safe operating temps

Popular Brands:

• Sonnax, Transgo, ATS Diesel, BD Diesel, and RevMax

 Compatibility and Swap Information

The Dodge 5.7L Automatic Transmission(545RFE) was used across several Chrysler platforms, making it a viable swap candidate for many V8 Dodge/Jeep/Chrysler projects.

Interchangeable Years/Models:

• Used in Dodge Ram 1500 from 2003 to 2011

• Also found in:

  • Jeep Grand Cherokee

  • Dodge Durango

  • Chrysler Aspen

  • Jeep Commander

Note: Swapping between model years requires attention to TCM programming and wiring harness compatibility.

 Evolution and Replacement

The Dodge 5.7L Automatic Transmission(545RFE) was eventually replaced by the 65RFE (in 2012) and later the 8-speed 8HP70 (starting in 2013 for some models), which offered smoother shifting, better efficiency, and modern gear ratios.

Improvements in Later Transmissions:

• Better fuel economy

• Tighter shift programming

• More available gear ratios for performance and efficiency

 Conclusion

The Dodge 5.7L Automatic Transmission(545RFE) transmission, when paired with the 5.7L HEMI V8, provides a capable and durable drivetrain for Dodge Ram 1500 trucks. Though it lacks the refinement of modern 8-speed units, it’s proven to be reliable when properly maintained. It offers adequate towing power, reasonable longevity, and an extensive aftermarket support network.

For owners and enthusiasts willing to maintain or upgrade, the Dodge 5.7L Automatic Transmission(545RFE) remains a solid platform that can serve reliably well beyond 200,000 miles. That said, understanding its limitations, addressing issues proactively, and keeping up with service will be key to getting the most out of this transmission.