My wifes 99 f150 transmission needs to be replaced the tag on her transmission
is XL3P-7000-AA.
Now the tag on the transmission i got to replace it is 3R3P-7000-BA which is out of a mustang I didn't know that at the time I just knew that it was a 4r70w and told that it would work for her truck.
the transmission looks the same with the exception of the tail shaft so can i just swap that and use an f150 torque converter and be ok any help is appreciated.

 

Yes, you can do that.

You do know that to swap the tailshaft you have to take the transmission COMPLETELY apart, right? Everything comes out of the trans, then you swap the shafts, then you rebuild the transmission.