99 expedition Tranny swap? 4.6l-5.4?
 

I just picked up a 99 ford expedition transmission. the tranny was ina 5.4 liter. i have a 4.6 liter. the tranny from the 5.4 is way bigger. is there ne thing i can do to make it work in my truck? the bolt patterns on the bellhousing are the same. I need to get my truck fixed. please help

To replace a 4R70W with a 4R100, you will need a new driveshaft, a computer out of a 4R100 vehicle, and some wiring mods. This assumes you are putting a 2wd tranny into a 2wd vehicle. If it's 4wd, there are more complications.

I'd look at trying to swap out your tranny for the right one. You shouldn't have a problem selling a 4R100. The right tranny needs to be out of the same drive type (2wd or 4wd).