[rotorwrench]

A person has to look around for even Mercon now days. I use Type F but it's even getting hard to source. If it's not been recently overhauled (last 20 years or so) then I'd avoid the synthetics. The old seals were not made for synthetics. Mercon will work but Type F will give a more positive shift if it still has the bronze & steel clutch plates. I'd drain it if I didn't know what was in it and start over. Some ATF types don't work well with others.