transmission fluid capacity

Complete Overhaul .................... 7.8L (8.2 Quarts)
Remove Drain Plug and Fill .................... 4.06L (4.29 Quarts)

There are some slight variables we need to know which transmission or engine you have, whether you are doing a flush, a filter and fluid change, or a total rebuild.

If just a service here is a guide that can help

https://www.2carpros.com/articles/how-to-service-an-automatic-transmission

As a general estimate, the typical three-speed automatic transmission holds around nine quarts, but only half of that drains out when doing a filter and fluid change.