2001 Camry-Solara Automatic Transaxle Diff Fluid Change Question

2001 Camry-Solara V6 Automatic 125K miles. I was changing the transaxle fluid when I noticed in the Haynes Repair Manual that you also need to change the differential fluid. The illustration in the manual clearly shows the location of the drain and fill plug on the diff. The casting depicted in the illustation looks identical to the one in my car except for the fill plug. The drain plug is in the same location as the illustration but there is no fill plug where the illustration shows one should be. There is just a flat surface between some cooling fins where the fill plug is suppose to be. I looked all over the casting and cannot see anything that looks like a fill plug in another location. Does anyone know if Toyota changed the design and the fluid is coming in from the tranny? If So do you need to still drain the differential? It doesn’t seem right that you would drain it and not have to fill it back up. Am I missing something here?