help with my trans leak please

[dandxg]

I have a 96 corolla dx with auto trans. It has a leak where the silver case meets a black housing between trans and engine I believe ( lame explanation I know, sorry ). It leaks a couple of drops on the driveway every other day, yet it shows on the full mark at hot. I wonder if the last mechanic whom did my trans flush overfilled it? Who knows my car has 162k on it. It has been 10k since my 30k service interval. It shifts well, drive well, I am just trying to take care of her, so she will make it to 200k club ( a payed off car getting 34 mpg on freeway is a good thing with these gas prices!). Can you folks tell what seal this is? Haynes hasn't a diagram or picture on this auto trans. Should I try to replace it. Can I do without pulling trans? I ask because haynes refers to some "drive oil seals" you can replace without pulling trans.

Also I plan on flushing engine and trans with auto-rx, seems like a decent product, and replacing fluids. Question, haynes says dextron II, can't find it, is it the same as dex III? I don't think I want to switch to synth trans fluid since I already have a leak. Thanks in advance for your help.