Where do you check and fill your rear differential???

[snowmobiler7c]

I have a 03 f250 7.3L 4x4. I just did a rear brake job and had to replace a wheel stud, so i pulled the axle out to get the hub off. Because of that i lost some rear dif fluid. I want to check and refill the rear dif but where is the fill area?? Most vehicles im use to have a plug you remove and fill to bottom of the plug and reinstall.

Is it where the sensor is on the top of the dif??? And if so how high do you fill it? And whats the recomended rear dif fluid? thanks
mark

[silverF250]

On our 00 and 01's there is a plug like the ones your familiar with. I haven't ever looked at an 03 but I assumed it would be the same.