Short answer
Mercon is Ford’s family of automatic transmission fluid specifications. Mercon V replaced the original Mercon, Mercon LV is a lower-viscosity fluid introduced in the late 2000s for newer Ford automatics, and Mercon ULV (WSS-M2C949-A) is an ultra-low viscosity fluid for the 10R80 10-speed. They are separate fluids, and Ford warns against using one where another is specified.
A short history of the Mercon names
Ford introduced the original Mercon specification in 1987. Mercon V followed and eventually took over Mercon applications as the remaining original Mercon licenses expired. Ford also used a Mercon SP fluid in some transmissions for a period.
Mercon LV (“low viscosity”) was launched as a separate fluid for Ford’s newer six-speed and later automatics and was designed to coexist with Mercon V rather than replace it. Mercon ULV came later for the 10R80 10-speed automatic used in the F-150 and Raptor and other Ford products.
Why the three are not interchangeable
Each Mercon fluid was paired with transmissions engineered around its viscosity and friction characteristics. Ford’s Motorcraft literature for Mercon ULV says not to use it where Mercon V, Mercon SP or Mercon LV is specified, because of its ultra-low viscosity. The same logic applies in the other direction: a thicker fluid in a ULV transmission is not what the transmission was calibrated for.
This is a change from earlier decades, when newer ATF specifications were often usable in older transmissions. With low and ultra-low viscosity fluids, the fluid has to match the transmission.
Ford specification numbers you may see
Ford engineering specifications use WSS-M2C numbers. Mercon ULV, for example, is WSS-M2C949-A. Labels and owner’s manuals may show the Mercon name, the WSS number, or both.
Ford licenses the Mercon name to fluid blenders, and licensed fluids are expected to show a license number on the container. Multi-vehicle fluids that say “for use in Mercon V applications” without a license are making their own claim.
Finding the right Mercon for a Ford
Check the owner’s manual fluid chart, the transmission dipstick or fill-plug marking where present, or ask a Ford parts counter to look up the VIN. Transmissions changed within model years and platforms, so the model year alone is not a reliable guide.
Then confirm that the fluid you intend to buy names that exact Mercon specification in its current product data.
Frequently asked questions
Can I use Mercon LV in place of Mercon V?
Ford treats them as separate fluids. Only substitute when Ford’s own service information says it is acceptable for that transmission.
What vehicles use Mercon ULV?
Motorcraft recommends Mercon ULV for the F-150 and Raptor with the 10R80 automatic. Other Ford 10-speed applications are listed in Ford service information and owner’s manuals.
Is Mercon ULV the same as GM Dexron ULV?
No. They are separate specifications written by different automakers for related 10-speed transmissions.
General maintenance information. Always follow your vehicle or equipment manufacturer’s requirements and the current product data. Questions? Email [email protected].
