If you own a 2007.5–2018 Dodge or Ram 2500/3500 with a 6.7L Cummins, there's a strong chance you've already thought about your 68RFE transmission — and for good reason. The 68RFE is one of the most debated transmissions in the diesel world: capable in stock form for light-duty use, but notoriously underpowered for the real-world punishment that Cummins owners dish out. BD Diesel has built their reputation on solving exactly this problem, offering a family of purpose-built 68RFE packages that range from daily-driver reliability to full-on high-horsepower abuse. This guide breaks down all three primary BD Diesel 68RFE transmission lines — the Roadmaster, Towmaster, and Torquemaster — explains what separates them, and helps you figure out exactly which one is right for your truck. We'll also cover the essential upsell upgrades that protect your investment and maximize performance.
Before diving into BD's solutions, it's worth understanding why the 68RFE has developed such a mixed reputation in the diesel community.
The 68RFE is a six-speed automatic transmission introduced by Chrysler in 2007.5 for the Ram 2500/3500 6.7L Cummins. It was essentially an adaptation of a gas-engine transmission pressed into diesel duty, and it shows. The case is relatively weak, the clutch packs are undersized for serious torque demands, and the valve body is cast from thin aluminum that can flex and allow hydraulic cross-leaks between clutch packs. The pump can barely provide adequate pressure at stock power levels, meaning the moment you add a tune, bigger injectors, or heavier tow loads, you're asking the 68RFE to do a job it wasn't originally designed for.
The most common failure points are well documented:
Weak torque converter — prone to ballooning, overheating, and shuddering under load
Valve body cross-leaks — separator plate and casting issues cause low line pressure and erratic shifts
Inadequate clutch packs — factory clutches wear quickly under heavy use and cannot hold higher torque
Overheating — the stock cooler and pan capacity are insufficient for towing or modified builds
Overdrive clutch failure — the OD shaft and clutch pack design are specifically prone to premature failure at higher power levels
These issues aren't just bad luck. They're predictable, engineered failures that BD Diesel has spent years diagnosing and correcting with their remanufactured transmission lineup. Every BD 68RFE goes through their in-house North American transmission shop, where specially trained technicians assemble and then dyno test every transmission and torque converter together as a matched set before shipping.
BD Diesel redesigned their transmission naming convention to make selection simpler: the name tells you the use case. Here's the quick framework — then we go deep on each one.
Best for: Daily drivers, lightly tuned trucks, and anyone who wants a more dependable replacement transmission without a big power bill.
The Roadmaster is BD's entry-level remanufactured 68RFE, and it's a significant step up from a stock replacement even though it's designed for trucks operating at or near stock power levels. Think of it as the "it's fixed and won't leave you stranded" tier. The core difference from a bone-stock unit is that every Roadmaster ships with the full BD Protect68 kit already installed — the upgrade that addresses the two most common early failure points: valve body cross-leaks and inadequate line pressure.
Roadmaster key upgrades:
BD Protect68 valve body with custom bonded gasket separator plate — eliminates internal cross-leaks that trigger OD clutch burn and limp mode
BD Pressure Enhancer module — raises line pressure up to 220 psi over the factory ~160 psi floor
BD Deep Sump aluminum oil pan — adds fluid capacity and heat dissipation fins to keep temps in check
Billet 4C spring retainer — addresses a known failure point in the stock unit
Stock clutch counts — the Roadmaster uses OEM clutch pack quantities; it's a reliability upgrade, not a capacity upgrade
BD ProForce torque converter — a forged billet cover single-disc unit with enhanced stator for better low-RPM efficiency and improved friction lining over stock
Warranty: 24-month parts / 12-month labor
The Roadmaster is ideal if your Cummins is running a mild tune (or no tune at all) with stock injectors and you primarily use your truck for commuting, light hauling, or occasional towing under 15,000 lbs. It's not the right choice if you're running big horsepower or planning on upgrading your engine in the future — you'll want to step up to the Towmaster or Torquemaster from the start rather than buying twice.
Best for: Heavy towers, work trucks, fleet operators, and builds with moderate power upgrades.
The Towmaster is where BD starts significantly strengthening the internal geometry of the 68RFE. This is the right transmission if towing is your primary use case — whether you're pulling a fifth-wheel, a loaded car hauler, heavy equipment, or just regularly running at or near GVW with your work materials. The Towmaster ups the ante over the Roadmaster in three critical areas: overdrive shaft, clutch count, and line pressure.
Towmaster key upgrades (everything in the Roadmaster, plus):
Custom Big Stack overdrive shaft — replaces the factory OD shaft, which is one of the most notorious weak points in high-load 68RFE applications
33% more overdrive clutches — achieved via BD's QT100 pressure plates that allow additional clutch counts without excessive deflection or distortion
33% more 2C clutches — steel girdle added to the 2C piston allows for a broader apply area
BD ProTech68 pressure control module — dynamically adjusts line pressure up to 250 psi based on MAP sensor (turbo boost/engine load)
Hard anodized valve body with new solenoid pack — every unit gets a fresh solenoid pack, eliminating an electrical wildcard
TCC limit valve — machined and sleeved to address the high-wear area inside the pump
BD ProForce torque converter — dyno tested with the transmission before shipping; enhanced stall stator, furnace-brazed turbine fins, 11.625-inch dual-clutch, billet forged front cover
Warranty: 36-month parts / 12-month labor / 150,000 miles
The jump from Roadmaster to Towmaster is meaningful: you're getting a genuinely reinforced gearbox that can handle sustained towing stress rather than a cleaned-up stock unit. The BD Big Stack OD shaft paired with increased clutch counts is particularly important for tow rigs, because the OD gear is under constant load during highway towing and is the first thing to fail when pressure drops or clutch capacity is exhausted.
Best for: High-horsepower performance builds, consistent heavy hauling, diesel enthusiasts who want zero transmission concerns as power goes up.
The Torquemaster is the performance tier — and the "BM" at the end of the part number stands for Billet Main (Input Shaft). This is the feature that separates it from the Towmaster: a 300M billet input shaft that absorbs rapid throttle shock and high-horsepower stress that would bend or crack the stock forged unit under aggressive conditions. Everything in the Towmaster carries over, but BD adds the billet shaft and upgrades the torque converter to their full triple-disc ProForce 3D unit.
Torquemaster key upgrades (everything in the Towmaster, plus):
Billet input shaft (300M steel) — handles the "snap" from aggressive throttle inputs and sustained high-horsepower loads; specifically designed for 500+ FWHP builds
ProForce 3D Triple-Disc torque converter — three clutch discs (vs. single or dual in lower tiers) with trapezoid tooth design for reduced wear and chatter, Torrington thrust bearings replacing plastic washers, riveted piston for alignment, and furnace-brazed turbine fins
Stamp forged one-piece converter cover — eliminates warpage from clutch heat, and the taller cover design allows multiple rebuilds over the converter's life
Engineered tighter tolerances — self-centering teeth design for maximum contact area
Reduced overall weight — 12 lbs lighter than comparable competitors
250 psi line pressure via ProTech68 module — same as Towmaster, ensuring maximum clutch clamp load at all times
Warranty: 36-month parts / 12-month labor / 150,000 miles
If you're running larger injectors, a compound turbo setup, or a performance ECM tune that puts you above 500 FWHP, the Torquemaster is the right call. The billet input shaft is the difference between a transmission that survives aggressive driving and one that doesn't — especially in trucks used for both towing and pulling at the strip or sled pulls.
A new BD Diesel transmission is a serious investment, and these add-ons ensure that investment lasts. Several are already in your catalog and ready for cross-linking.
The factory stamped-steel flexplate is under-engineered for the torque that a Cummins produces — especially on modified trucks. Under high power and aggressive engagement, the stock plate can crack or shatter, taking the torque converter with it.
The BD Diesel FleX-Plate (PN: 1041221) — available at NorCal Diesel Performance — is forged billet steel with twice the material of the stock unit, rated for over 2,000 lb-ft of torque standard and up to 3,500 lb-ft with BD's optional Slip Eliminator shim kit. It's SFI 29.3 certified for race applications and black oxide coated for corrosion resistance. It installs directly in place of the factory unit, compatible with all OEM and aftermarket torque converters. Torque specs: 100 ft-lbs to crank, 65 ft-lbs to torque converter for 6.7L engines.
If you prefer an ATS unit, the ATS 68RFE Billet Flexplate (PN: 305-900-2326) for 2007.5–2018 is also available in the catalog, and for 2019+ trucks, the ATS 68RFE Billet Flexplate (PN: 305-900-2464) is here.
Recommendation: Pair a billet flexplate with any Towmaster or Torquemaster purchase. It's cheap insurance against a catastrophic converter/flexplate failure.
If you're running a stock or moderately upgraded 68RFE and want to improve clutch holding capacity without a full transmission replacement, BD's standalone pressure controllers are the most cost-effective upgrade available.
BD Diesel Transmission Pressure Enhancer (PN: 1030369) — available at NorCal Diesel Performance — is the full-featured pressure control module. It delivers up to 250 psi of clutch apply pressure and dynamically adjusts hydraulic pressures based on turbo boost and engine load. This module requires BD's separator plate kit or a comparable valve body modification to support the higher line pressure, making it the right choice for partially built transmissions or as a standalone upgrade before a full rebuild.
This is also the same pressure control module included in every Towmaster and Torquemaster, so buying it separately is ideal for Roadmaster owners who want to push a bit more power without stepping up to a full new transmission.
For a simpler, plug-and-play pressure upgrade, the BD Diesel Electronic PressureLoc (PN: 1030368-V2) — available at NorCal Diesel Performance — is an inline plug module that requires no transmission disassembly.
Here's how it breaks down vs. the Pressure Enhancer:
Delivers 10 psi increase at lower pressure range, 25 psi at higher pressure ranges
Progressive pressure increase — smooth engagements with lower pump load at idle
Integrated advanced control chip eliminates the occasional error code caused by older resistor-based devices
Does not require a separator plate modification — works on completely stock transmissions
Ideal for lightly tuned or stock trucks wanting improved shift firmness and clutch longevity
The PressureLoc is the right call for Roadmaster-level builds or stock transmissions running a mild tune. If you're at Towmaster or Torquemaster territory, the full Pressure Enhancer (1030369) is the better fit because the ProTech68 module already includes more aggressive dynamic pressure control.
The factory transmission cooler bypass valve on 2013–2024 Ram trucks is one of the most underappreciated failure points on the platform. The bypass valve is designed to recirculate transmission fluid until it reaches operating temperature, bypassing the external cooler. The problem: debris in the system can jam this valve in the closed position, meaning your transmission fluid never reaches the cooler — and you don't know until your transmission temperature spikes.
On the 2013–2018 trucks, the factory bypass valve also has a significant internal restriction that can reduce cooler flow by up to 87% even when open.
BD Diesel Cooler Bypass Delete — 2013–2018 (PN: 1061528) is available at NorCal Diesel Performance. It's a billet aluminum direct replacement that ensures 100% fluid flow through the transmission cooler at all times.
BD Diesel Cooler Bypass Delete — 2019–2024 (PN: 1061527) is available at NorCal Diesel Performance for newer trucks.
For 2013–2018 trucks who want a bypass with a better thermostat rather than full delete, the RevMax 68RFE Thermal Bypass Valve Upgrade is also available at NorCal Diesel Performance. This billet 6061 unit uses RevMax's ZeroStat Technology to eliminate the orifice restriction for full unrestricted cooler flow and reportedly reduces transmission inlet temps by up to 40°F.
Installation time: 30 minutes — arguably the easiest transmission upgrade you can do, and critically important for any towing application.
Heat is the number-one killer of automatic transmissions, and the factory 68RFE cooler is sized for light-duty use, not the real-world punishment of pulling a 30,000-lb fifth-wheel across the Sierra Nevada in July. If you're investing in a BD transmission, a high-capacity cooler is not optional — it's part of protecting that investment.
Mishimoto makes year-specific direct-fit coolers for the Ram 6.7L platform. Here's where things stand on your site:
✅ Available at NorCal — 2015–2018 Ram 6.7L Cummins:
The Mishimoto MMTC-RAM-15SL transmission cooler is available at NorCal Diesel Performance. It features a tube-and-fin core with internal fins for maximum fluid contact, a massive 112% increase in core volume, 237% increase in external fin area, and 226% increase in fluid capacity over the stock cooler. Bolt-on installation, no cutting required, backed by Mishimoto Lifetime Warranty.
2007.5–2009 Ram 6.7L Cummins: Mishimoto MMTC-RAM-03SL — 212% increase in core volume, 244% increase in fluid capacity, stacked-plate design, includes removable thermostat and thermostat bypass
2010–2012 Ram 6.7L Cummins: Mishimoto MMTC-RAM-10 — 60% increase in core volume, tube-and-fin design for heavy towing
2013–2014 Ram 6.7L Cummins: Mishimoto MMTC-RAM-13SL — direct fit with 64% thicker core over stock
2019+ Ram 6.7L Cummins: Mishimoto MMTC-RAM-19 — 17 rows, tube-and-fin with internal fins, 64% thicker core over stock
BD Diesel Deep Sump Trans Pan (PN: 1061525) — available at NorCal Diesel Performance — already included with all BD transmission packages, but available as a standalone for trucks that aren't getting a full transmission swap. Adds extra fluid capacity and case flex reduction.
PPE HD Transmission Pan (Raw) — available at NorCal Diesel Performance — a heavy-duty cast aluminum alternative pan with increased capacity, made for the same 2007.5–2017 68RFE application.
Here's how to build a complete package around each BD transmission tier:
BD Diesel Roadmaster 68RFE (1064224SS)
BD Diesel Electronic PressureLoc (1030368-V2) — optional upgrade for mild tune
BD Diesel FleX-Plate (1041221) — highly recommended
Mishimoto Transmission Cooler (year-specific) —
BD Diesel Cooler Bypass Delete (1061527 or 1061528, 2013+ trucks) — 2013–2018 | 2019–2024
BD Diesel Towmaster 68RFE (1064264SS)
BD Diesel FleX-Plate (1041221) — strongly recommended
Mishimoto Transmission Cooler (year-specific) —
BD Diesel Torquemaster 68RFE w/ Billet (1064264BM)
BD Diesel FleX-Plate (1041221) — essential
BD Diesel Transmission Pressure Enhancer (1030369) — for built trucks running the ProTech68 independently
Mishimoto Transmission Cooler (year-specific) —
BD Diesel Billet Input Shaft (1600189) — if purchasing shaft separately for a rebuild
Which BD Diesel 68RFE is right for a tuned truck towing a fifth wheel?
The Towmaster (1064264SS) is the sweet spot for most tow-focused builds. It adds the Big Stack OD shaft, increased clutch counts, and 250 psi line pressure that stock-level builds can't sustain on extended grades under load. If you're running a big single or compound turbo with significant injector upgrades, step up to the Torquemaster.
Do I need a tune after installing a BD Diesel 68RFE transmission?
BD's transmissions come with the ProTech68 pressure control module that dynamically adjusts pressure based on MAP sensor input, so a dedicated transmission tune is not required. However, a transmission-aware tune from a reputable tuner (EFI Live, HP Tuners) that coordinates shift points and torque reduction during gear changes will maximize the transmission's longevity.
What is the estimated install time?
BD rates all their 68RFE transmission packages at approximately 9 hours for installation. A competent diesel shop should have it done in a day or two.
Is the 68RFE good for diesel drag racing?
The Roadmaster and Towmaster are not rated for race abuse — BD explicitly excludes race use from warranty coverage. The Torquemaster is the right starting point for performance builds, and BD's TrackMaster tier is the proper choice for competitive racing applications.
What transmission fluid does the 68RFE take?
Mopar ATF+4 is the factory-specified fluid for the 68RFE. Use of ATF+4 certified replacements is acceptable. We recommend a good name brand such as Amsoil, Royal Purple, Redline etc. Using cheap fluids can lead to shifting issues, solenoid wear, and premature failure. Change intervals for built transmissions: every 30,000–50,000 miles or annually for heavy tow applications.
The 68RFE is not a bad transmission — it's just a transmission that was designed with a narrower duty cycle than most Cummins owners operate in. BD Diesel's three-tier lineup gives you a clear upgrade path regardless of where you are in your build:
Roadmaster if reliability is the goal and power is stock
Towmaster if the truck works for a living and tows heavy on a regular basis
Torquemaster if power is the priority and you want a transmission that keeps up with your engine
Pair any of these with a billet flexplate, the appropriate pressure controller, and a year-matched transmission cooler with bypass delete, and your 68RFE will outlast everything else on the truck.
Have questions about which BD Diesel 68RFE package is right for your build? Contact the team at NorCal Diesel Performance or call 888-290-3820.
