When it comes to heavy-duty trucks, few debates are as heated as the one between two transmission giants: the 68RFE and the Allison 1000/2000 series. Whether you’re hauling loads across the country or towing heavy equipment locally, the transmission under your hood can make or break your truck’s performance, reliability, and longevity.
So, which one truly reigns supreme—the 68RFE or the Allison? Let’s break down this epic battle.
Understanding the Contenders
68RFE Transmission
The 68RFE (Refined Frequency Electronically controlled) is a 6-speed automatic transmission built by Chrysler. It debuted in 2007 and is primarily paired with 6.7L Cummins diesel engines in Ram 2500 and 3500 heavy-duty trucks. The transmission was designed to balance both fuel efficiency and torque demands of diesel-powered workhorses.
Allison 1000/2000 Series Transmission
The Allison 1000 transmission and 2000 series transmissions are built by Allison Transmission, a company with a century-long legacy in automatic transmission systems for both commercial and military applications. The Allison is often matched with Duramax diesel engines in Chevrolet and GMC HD trucks. Known for durability and performance, it’s often praised for its smooth shifting and heavy-load endurance.
Torque Handling and Towing Capacity
- 68RFE: The 68RFE handles up to 800 lb-ft of torque in its factory configuration. While respectable, this torque limit can become an issue when upgrading power or towing extreme weights.
- Allison: Allison 1000/2000 series transmissions are known to handle over 1,000 lb-ft of torque, especially when tuned or paired with a high-output Duramax. It’s a favorite for those doing serious heavy hauling or fifth-wheel towing.
Winner: Allison. When it comes to raw torque handling, the Allison wins hands down.
Durability and Reliability
68RFE
The 68RFE has had its share of reliability complaints over the years. Weaknesses include:
- Soft internal clutches
- Valve body issues
- Inconsistent line pressure This transmission often requires aftermarket upgrades (like billet torque converters and valve body kits) to handle extreme duty cycles.
Allison
The Allison transmission has a reputation for long-term durability, especially when properly maintained. It features:
- Adaptive shift technology
- Robust torque converter
- Superior clutch packs It’s trusted in commercial fleets and buses, a testament to its rugged design.
Winner: Allison. Proven durability in both commercial and consumer trucks makes it a solid choice for reliability.
Shift Quality and Performance
- 68RFE: Often criticized for its sluggish and inconsistent shifts, especially under heavy load or with larger tires. However, it can be improved with tuning and upgrades.
- Allison: Offers smooth, consistent shifts and performs well under load, thanks to its adaptive learning technology that adjusts shift points based on driving conditions.
Winner: Allison. Its superior software and hardware integration results in a better driving experience.
Aftermarket Support and Upgrades
- 68RFE: Thanks to its widespread use among Cummins enthusiasts, there’s extensive aftermarket support. Many opt to rebuild or upgrade their 68RFE with stronger internals, valve bodies, or even switch to the 48RE or 47RE for extreme applications.
- Allison: While strong out of the box, Allison transmissions also enjoy strong aftermarket support, though parts and labor can be more expensive.
Winner: Tie. Both transmissions have solid aftermarket options, but the 68RFE might be more cost-effective to upgrade.
Cost and Maintenance
- 68RFE: Factory replacement or rebuild is generally less expensive than an Allison. However, due to its limitations, you may spend more over time on repairs or upgrades.
- Allison: Known for low maintenance needs and longer service intervals, but replacement parts and fluids (TES 295) are pricier.
Winner: 68RFE (initially), but long-term cost-efficiency may favor Allison.
Stock vs. Modified Performance
If you’re planning to tune or modify your diesel engine for added power, transmission compatibility becomes critical.
- 68RFE: Often struggles with tuned Cummins engines, especially above 450 horsepower. Without internal upgrades, it can fail under power increases.
- Allison: More forgiving of performance upgrades and can withstand moderate tuning with minimal modification.
Winner: Allison. Handles tuning better without requiring a full rebuild.
Real-World Applications
Ram Trucks (68RFE)
- Ideal for daily drivers and weekend haulers
- Needs upgrades for commercial-level towing or horsepower gains
- Affordable to repair but not the most durable under extreme conditions
GM Trucks (Allison)
- Performs well for daily, commercial, and heavy-duty applications
- Built with longevity in mind
- Higher initial cost but fewer long-term issues
What About the Aisin?
It’s worth noting that Ram trucks now offer the Aisin AS69RC in place of the 68RFE on some high-output Cummins variants. It’s more in line with the Allison in terms of capability, but still hasn’t earned the same level of trust in aftermarket and commercial circles.
Verdict: Which One Wins?
| Category | Winner |
|---|---|
| Torque Handling | Allison |
| Durability | Allison |
| Shift Quality | Allison |
| Aftermarket Support | Tie |
| Cost & Maintenance | 68RFE (short term) |
| Tuned Performance | Allison |
Overall Winner: Allison Transmission
If you’re seeking a transmission that’s reliable, shift-smooth, and ready to take on high torque loads or heavy-duty towing, the Allison transmission is the clear winner. It’s built to handle stress and rarely needs help doing its job.
However, if you’re working with a Cummins-powered Ram and want to save money upfront, the 68RFE still has a place—especially when paired with smart tuning and key upgrades.
Ultimately, your decision should be based on your truck’s workload, budget, and future power goals.
Final Thought:
In the world of heavy-duty trucks, transmission choice is just as critical as engine selection. Whether you’re loyal to the Cummins-Ram camp or a die-hard Duramax-GM fan, make sure your transmission is ready for the long haul.
