When I changed my u joints, I lost some trans (?) fluid, how do i replace it?

It%26#039;s not out of the rear diff, although that is leaking as well!|||if it is a manual transmission .. there is 2 plugs in the side of the transmission top is to add, bottom is to drain. and i would fix the leak in the rear end too.. new seal and gasket it only a 1 hour job.. runing it lowin oil will wear out the rear end and Axel bearings .. i have seen the bearings seize up and a rear wheel break off and role down the road.... so fix the leak....|||i%26#039;m not totally sure what you%26#039;re asking but for tranny fluid you usually need a funnel; just pour the fluid in where the dip stick is.|||It is usally a square hole on the side of the trans that a 3/8 drive ratchet will fit into. There will be one on the side to fill and one on bottom to drain. Check with your local parts store for proper fluid to fill with , some of the newer will require synthetic fluid. If dont see the square hole it may be a bolt on the side you remove to fill.|||There is a plug on one side or the other that will be your fill point.;..