Dodge Caravan 92

I got a dodge grands caravan 92, 3, 3l, 272386 and I got a leak from the left side of the transmission. I can see it when I took of the wheel and does not seems to be transmission fluid. (Some kind of gear box). I could repair the gasket but a wonder what to put in it after. So if you could tell me what kind of oil or grease I need it would be appreciate.

Thank you
Jonathan Thibodeau