On a 91 v6, are you suppost to use dexron ll atf?

If you have an automatic transmission, yes dextron II in the transfer case.

I checked Mitchell On-Demand, and it said all 91 pick-ups and 4Runners use dexron II and the refill capasity is .85 quarts.

It dpesnt matter whether its auto or manual?

Yes only the automatic transmission takes dextron II ATF in the transfer case. What do you have? The auto or manual? You didn't tell us so I was just guessing that you have the auto. You can fill in the rig section of your profile or just put it in the signature line of your post, or type it in everytime you post. But the more details you tell us the better we can help you.

The manual tranny version of the transfer case uses 75w90 or 80w90. The auto tranny version allows fluid to be shared between the tranny and transfer so it takes Dexron II.

So there is sharing of bodily fluids huh? I always wondered about that.

Its only shared on the auto. The manual has a seal between the tranny and transfer.