My g/f's 1994 Explorer needs tranny fluid. From what I can see online is that it can take either Mercon or Mercon V fluid. Problem is, we don't know what kind is in there to begin with. I bought a quart of Mercon V but before I dump it in there, is it okay to mix Mercon and Mercon V (in case that the fluid already in the tranny is Mercon and not Mercon V).

I tried searching online but there isn't really anything definitive I feel like trusting and was wondering if anyone here happens to know. Thanks.