Although MERCON V was cross-compatible with MERCON ATF in transmissions, it was not to be used in transfer cases. This was not an issue, however, because MERCON ATF remained in production. The Ford F-Series owner manuals continued to call for MERCON fluid through the 2007 model year, but the production of MERCON ATF ceased in July of 2007. TSB 06-14-04 announced the end of production and provided guidance that MERCON V is a direct replacement, but it does not address its usage in transfer cases.
Despite some early confusion, Ford did launch a suitable replacement for transfer cases: Motorcraft XL-12 transfer case fluid. Its first appearance was in the transfer case fluid specification for the 2008 Ford F-Series. XL-12 superseded the previous MERCON specification, thus any transfer case model with this requirement would use XL-12 moving forward.
XL-12 transfer case fluid remained the specification through the 2016 model year, but MERCON LV automatic transmission fluid became the transfer case fluid specification beginning with the 2017 Super Duty. XL-12 was available until production ceased in 2019. MERCON LV supersedes all transfer cases that had the XL-12 requirement, therefore MERCON LV automatic transmission fluid is the correct replacement fluid for all transfer cases with the old MERCON specification. As of 2026, based on the Ford Super Duty owners manual, MERCON LV remains the required transfer case lubricant.
MERCON LV is a low viscosity, full synthetic automatic transmission fluid used in the 10 speed family of transmissions, but it also supersedes all MERCON SP requirements; MERCON SP production ceased in 2023, as announced in SSM 51909.
It is noted in various service materials that MERCON LV is "for use in all transfer cases". The label on each bottle states it is "recommended for use in automatic transmissions and transfer cases where MERCON LV is specified." Although the lack of a connection to the old MERCON spec may be confusing to some, it is the correct replacement.
Do not use MERCON ULV (ultra-low viscosity transmission fluid) in a transfer case unless it is specifically called for in the owner's manual. For all transfer cases with a MERCON requirement, use MERCON LV.
Compatible Equivalents
Note that each of these transmission fluids are full synthetic lubricants. Per their respective manufacturer, they meet or exceed the MERCON LV fluid requirements.
- Amsoil Signature Series Fuel Efficient ATF
- Amsoil OE Fuel Efficient ATF
- Lucas Oil Multi-Vehicle Low Viscosity ATF
- Castrol Transmax Dexron VI MERCON LV
- Valvoline Dexron VI/Mercon LV
