ATF WITH STOP LEAK Leakages in car transmission can occur because of dry and hardened gaskets and seals. You can stop these leakages by adding a bottle of MAG 1 ATF WITH STOP LEAK into the automatic transmission during replacement or top-up of transmission oil. DEXRON®-III / MERCON® replacement (an additive to soften and improve seals and gaskets). Benefits: • Protection of gaskets and seals. • Excellent protection of high and low temperatures. • Resistant frictional properties for smooth and consecutive gear shifting. • Excellent stability.