These look identical on the shelf — both are low-viscosity automatic transmission fluids. But they are NOT cross-compatible. Mixing them in the wrong transmission causes shudder, harsh shifts, and premature wear within 5,000 miles.
GM-spec fluid for 4L60E, 4L65E, 4L80E, 4L85E, 6L80, 6L90, 8L90, 10L80, and Allison 1000. Replaces Dexron III in legacy applications. Synthetic blend, low viscosity (5.8 cSt at 100°C).
Ford-spec fluid for 6R60, 6R75, 6R80, 6F35, 6F50, 6F55, and 10R80. Synthetic, lower viscosity than Mercon V (4.5 cSt at 100°C). Designed for Ford 6-speed and 10-speed planetary friction packs.
Different friction modifiers. Dexron VI is calibrated for GM clutch material; Mercon LV for Ford. Using the wrong one causes: shudder under load, harsh 2-3 shift, slipping converter lockup, and accelerated clutch wear. Once contaminated, the only fix is a triple flush.
GM 4L60E/6L80: Dexron VI ONLY.
Ford 6R80/10R80: Mercon LV ONLY.
Dodge 68RFE: ATF+4 (neither of these — separate spec).
Allison 1000: Dexron VI or TES-295 only.
Direct-from-the-pro pricing. Free shipping over $75. Same-day handling Monday-Friday.
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