Where do you add transmission fluid to a 1990 corolla with an automatic transmission?

The service manual says to add fluid through the dipstick channel. If you open the hood and stand in front of the car you should be able to see the dipstick handle for the automatic transmission on the left side (passenger side) of the battery. There is another place where automatic Transmission Fluid is needed. It wouldn't surprise me if many do-it-yourself Corolla owners never think to change the fluid in the differential case. But if they have their inner CV joints changed, this fluid is changed for them. The maintenance schedules in the service manual don't show how often the fluid should be changed. I suspect its good for tens of thousands of miles. Under the front of the car you will see that the "axles" or CV joints go from the wheel toward the middle of the car into what looks like part of the transmission. This "differential case" is a separate reservoir from the automatic transmission. There is a large bolt on the rear of this case. Taking off this bolt, transmission fluid is added by pumping it into this hole until it begins to overflow out the hole. (You can get small inexpensive hand operated pumps for this job at an auto parts store. ) If you buy a used 89-92 Corolla, you may find that someone has put "gear oil" instead of transmission fluid in this compartment. The service manual definitely says to use transmission fluid, not gear oil. However, it didn't seem to hurt anything in the one I bought. When I changed the CV joints, I let the gear oil drain out. I replaced it with transmission fluid.