rear diff questions

'97 tacoma on the diff there's the drain plug and fill plug for gear oil, but on the top of the diff just to the left if facing it from the back is a small little plug that unscrews what's that for?

I can't get the fill plug off so i was wondering if i could fill it from there?

And are the little nipples on the backing plates on the back of the drums for the bearing grease?

you must use the fill plug. you cant just fill the rearend. you have to put oil through the fill plug hole until it starts to seep out the fill hole. those nipples your refering to are not grease zerts. they are bleeder screws where you bleed your brakes from. do not fill them with anything.

you must use the fill plug. you cant just fill the rearend. you have to put oil through the fill plug hole until it starts to seep out the fill hole. those nipples your refering to are not grease zerts. they are bleeder screws where you bleed your brakes from. do not fill them with anything.