Wanting to replace the gear oil in my 1994 4 cyl Nissan Hardbody King Cab 4x4 pickup. Is this my front differential?

Two views shown below - (a) front facing forward (I think it shows the check/fill plug) and (b) bottom (I think it shows the drain plug). Both photos taken from under front bumper. Thanks!

 

Yes, remove the bottom plug to drain, screw it back in and fill thru the top plug.

 

Hey while we're on the topic, the manual says to use a 1/2" socket adapter. It fits kind of sloppy and I'm afraid of damaging something. Is there a special wrench for these plugs?

 

Just a thought,it might be metric.

 

I've always used just the ratchet or ratchet plus extension. Some plugs seem to have a tighter fit than others, same thing with the extensions.