WSS M2C938 A
Understanding the precise technical parameters of Ford engineering specification WSS M2C938 A is vital for maintaining the performance, fuel economy, and shifting longevity of modern Ford, Lincoln, and Mercury vehicles. In the automotive lubrication industry, Ford Motor Company designates proprietary chemical standards using its alphanumeric Worldwide Standards System (WSS). Specifically, WSS-M2C938-A is the official factory engineering material specification that defines Motorcraft MERCON LV Automatic Transmission Fluid. Engineered specifically for electronically controlled, tight-tolerance multi-speed automatic transmissions and hydraulic power steering systems, this advanced low-viscosity formulation provides superior anti-shudder friction durability, exceptional shear stability, and outstanding low-temperature cold-weather fluidity across millions of modern commercial and passenger vehicles.
Alphanumeric Specification Decoding and Chemical Architecture
To understand automotive fluid standards, it helps to decode what the alphanumeric designation WSS-M2C938-A actually stands for under Ford's global engineering protocol. The prefix 'WSS' stands for Worldwide Sourcing Specification (or Worldwide Standards System), indicating that this standard applies universally across all Ford manufacturing and assembly facilities globally. The letter 'M' designates the Materials Engineering classification. The sub-code '2C' specifies the internal lubrication category for oils, hydraulic fluids, and greases. The unique numerical sequence '938' identifies this exact chemical formulation, while the terminal letter 'A' indicates the original base revision level of the standard.
Chemically, fluids meeting WSS-M2C938-A represent a major technological leap over earlier generation transmission fluids like MERCON V. Formulated with high-viscosity-index hydrocracked Group III synthetic base stocks, MERCON LV features a lower kinematic viscosity (approximately 6.0 centistokes at 100 degrees Celsius, compared to 7.5 cSt for older fluids). This lower viscosity reduces parasitic fluid drag within planetary gear sets, contributing directly to improved vehicle fuel efficiency. Furthermore, specialized organometallic anti-wear additives, friction modifiers, and oxidation inhibitors prevent clutch plate glazing, foam aeration, and high-temperature thermal breakdown.
Review the chemical properties, physical benchmarks, and performance standards of Ford specification WSS-M2C938-A below:
| Physical / Chemical Property | Standard Testing Method | Engineering Benchmark Value | Functional Drivetrain Benefit |
|---|---|---|---|
| Kinematic Viscosity @ 100°C | ASTM D445 | 5.8 to 6.2 cSt (Low Viscosity) | Minimizes hydraulic pumping loss; boosts fuel economy |
| Kinematic Viscosity @ 40°C | ASTM D445 | 29.0 to 31.5 cSt | Ensures immediate hydraulic line pressurization |
| Viscosity Index (VI) | ASTM D2270 | Minimum 150 to 160 | Maintains stable fluid viscosity across -40°F to 300°F |
| Flash Point (Cleveland Open Cup) | ASTM D92 | Minimum 200°C (392°F) | Resists thermal vaporization under extreme towing |
| Brookfield Viscosity @ -40°C | ASTM D2983 | Maximum 12,000 mPa·s (cP) | Instant sub-zero cold-crank shifting; zero clutch delay |
| Anti-Shudder Friction Durability | JASO M349 / SAE No. 2 | Exceeds 30,000 test cycles | Eliminates torque converter clutch shudder and chatter |
Fluids meeting WSS-M2C938-A are dyed red to distinguish them from motor oils and make transmission leaks immediately noticeable.
Vehicle Compatibility, Transmission Models, and Interchangeability
Ford specification WSS-M2C938-A is mandated across a vast lineup of modern Ford vehicles equipped with 6-speed and selected 10-speed automatic transmissions. Common transmission models requiring this fluid include the front-wheel-drive 6F35 and 6F55 transaxles found in the Ford Fusion, Edge, Escape, and Explorer, as well as the heavy-duty rear-wheel-drive 6R80 and 6R140 transmissions installed in the Ford F-150, Super Duty, Expedition, and Mustang. It is also the designated fluid for electronic hydraulic power steering systems in older Ford Focus and Fusion models.
A critical rule for mechanics and vehicle owners is understanding strict fluid interchangeability. WSS-M2C938-A (MERCON LV) is NOT backward compatible with transmissions that specifically call for older MERCON V (WSS-M2C202-B) or original Type F fluids. Using low-viscosity MERCON LV in older 4-speed 4R70W or E4OD transmissions can cause clutch slippage, premature planetary gear wear, and solenoid failure. Conversely, using thick MERCON V in a modern 6-speed transmission requiring WSS-M2C938-A will cause harsh shifting, sluggish cold-weather gear changes, and torque converter lockup shudder.
Review transmission models, vehicle pairings, and fluid service capacities governed by WSS-M2C938-A below:
| Transmission Model | Representative Ford / Lincoln Vehicles | Fluid Capacity (Pan Drop / Dry) | Specific Service Notes |
|---|---|---|---|
| Ford 6R80 6-Speed Automatic | Ford F-150, Expedition, Mustang (2009–2017) | 7.0 qts (Pan drop) / 13.1 qts (Dry fill) | Requires checking level via mini dipstick on transmission case |
| Ford 6F35 6-Speed Transaxle | Escape, Fusion, Edge 1.5L/2.0L/2.5L | 4.5 qts (Drain & fill) / 9.0 qts (Dry) | Equipped with side leveling plug; change every 30k–50k miles |
| Ford 6F50 / 6F55 Heavy FWD | Explorer, Taurus SHO, Flex 3.5L EcoBoost | 5.0 qts (Drain & fill) / 11.0 qts (Dry) | Handles high-torque EcoBoost turbo power; monitor fluid heat |
| Ford 6R140 TorqShift 6-Speed | F-250 / F-350 Super Duty 6.2L / 6.7L | 8.0 qts (Service) / 17.5 qts (Total) | Heavy commercial towing fluid; inspect annually |
| Electronic Hydraulic Power Steering | Ford Focus, C-Max, European Transits | 0.8 to 1.2 qts (System capacity) | Prevents pump whining and seal hardening |
Never use multi-vehicle fluids unless the packaging explicitly states licensed compliance with Ford WSS-M2C938-A / MERCON LV.
How to Verify and Service WSS-M2C938-A Fluid in 4 Steps
Follow this practical mechanic procedure to verify specification compliance and service transmission fluid.
Confirm Specification in Vehicle Owner's Manual
Open your vehicle handbook to the 'Capacities and Specifications' section to verify the transmission mandates WSS-M2C938-A / MERCON LV.
Purchase Licensed Motorcraft or Approved Fluid
Procure genuine Motorcraft MERCON LV or top-tier synthetic fluids (like Valvoline MaxLife) explicitly certified to WSS-M2C938-A.
Drain Old Transmission Fluid and Replace Filter
Drain fluid via pan removal or drain plug, clean internal magnet of metal shavings, and install a fresh internal transmission filter.
Fill and Verify Fluid Level at Operating Temp
Refill with fresh fluid, run the engine until the transmission reaches 190°F–200°F, and check the level using the dipstick or side inspection plug.
Frequently Asked Questions (9 Questions Answered)
Q1: What does WSS stand for in Ford specifications?
In Ford engineering standards, WSS stands for Worldwide Sourcing Specification (or Worldwide Standards System), indicating a global engineering material standard.
Q2: Is WSS-M2C938-A the same as MERCON LV?
Yes, WSS-M2C938-A is the internal Ford engineering material specification number for Motorcraft MERCON LV (Low Viscosity) automatic transmission fluid.
Q3: Can I use MERCON V instead of WSS-M2C938-A?
No, MERCON V has a higher viscosity and different friction chemistry. Using MERCON V in a transmission requiring WSS-M2C938-A can cause harsh shifting and damage.
Q4: What does the 'LV' stand for in MERCON LV?
'LV' stands for Low Viscosity. It is engineered with thinner base oils to reduce internal fluid drag, boosting overall vehicle fuel economy.
Q5: Can I use Dexron VI in place of WSS-M2C938-A?
While both are low-viscosity fluids, GM Dexron VI and Ford MERCON LV use different friction modifier packages. Only use multi-vehicle fluids certified to both.
Q6: How often should WSS-M2C938-A transmission fluid be changed?
Ford officially suggests 150,000 miles under normal conditions, but experienced mechanics strongly advise changing fluid every 30,000 to 60,000 miles for long-term reliability.
Q7: What color is WSS-M2C938-A fluid?
WSS-M2C938-A fluid is dyed bright red to distinguish it from motor oil and amber brake fluid, allowing drivers to identify transmission leaks easily.
Q8: What happens if you put the wrong fluid in a Ford 6R80 transmission?
Putting non-LV fluid in a 6R80 causes torque converter clutch shudder, delayed engagement when cold, and accelerated wear on internal clutch bands.
Q9: Does WSS-M2C938-A fluid expire in an unopened bottle?
In sealed, factory-capped plastic containers stored in dry, moderate temperatures, synthetic transmission fluid has an exceptional shelf life of seven to ten years.
Final Thoughts & Key Takeaways
In conclusion, understanding wss m2c938 a provides essential clarity, practical strategies, and actionable advice. By incorporating these foundational insights, adhering to verified safety guidelines, and following structured best practices, you ensure reliable, long-term outcomes while preventing common mistakes. Stay informed, consult certified professionals when needed, and maintain consistent quality care.