Fill differential through speed sensor hole.
haha, yeah, I'd hate to drain it and then find that I cant break the fill plug loose.
Come on, in Camry it's not a problem.
You can always fill differential via speed sensor hole (it's even easier).
BTW, in 18 years old car you can expect leaks after oil change in differential, because of worn axles seals or most stupid thing that I have ever seen: deep inside differential is a aluminium plug with o-ring (if this fail there will be differential oil escaping from gap between transmission and engine).
If you don't know what I'm talking about, peep this...
Gear that powering differential has one bearing (from overdrive unit side, lef side), and on the opposite side (right) is aluminium plug (it seals differential compartment from torque converter cavity).
This stupid thing is bolted (10 mm head screw) from torque converter side.
There is ordinary small o-ring (if it fails, you will loose all differential oil).
What's the purpose of this?
Japanese engineers are sometimes genius, sometimes stupid and retarded.