Do you have to remove your transmission out of ford expedition replace the rear seal?

No, you generally do not have to remove the entire transmission from a Ford Expedition to replace the rear main seal. While it's a challenging job, it's usually possible to access and replace the seal with the transmission in the vehicle. However, it requires dropping the driveshaft and likely removing the transmission crossmember for better access. The exact procedure varies slightly depending on the year and model of the Expedition. A repair manual specific to your vehicle's year and engine will provide the most accurate instructions.