They are both AODE transmission but the 4r75W is a more modern. It just has some upgraded components and improvements made to the 4R70W. The components are mostly the same inside the units but the electronics are difference. Like the 75 has two speed sensors and the 70 only has an output speed sensor.
This means they are not interchangable even though they will bolt up in place of each other. So you will just need to know which one you are getting as some 5.4L could have the 75 if you have the 70 or the vice versa.
Let us know if you have other questions. Thanks
Friday, January 15th, 2021 AT 6:05 PM