61 4dr. 2 speed merc o matic.....trans. gasket replace

[61 Waycrosscomet]

I will be replacing my transmission gasket. Because of previous issues with the little transmission sensor i have basically replaced all the fluid
already. Won't be draining the stater?.
After I clean filter and replace gasket, is there anything special i need to do, other than putting the fluid back in?

thanks. johnm