the adapter for AOD-E to BW 1354 t case requires you to replace the output shaft in the transmission with a unit supplied to you with the adapter.
This means the transmission must be pulled and basically rebuilt.
Adapter was $550 or so, the work I had done to my 4r70w was about $700, but I had some soft parts replaced in my 50K miles trans.
just FYI, it's not as simple as you might think to retain the BW1354 T case
Now you can also use a AOD to D20 t case adapter and spud shaft, this does not require the 4r70w to be removed and dis-assembled. This allows you to run a D20 t case, an excellent choice for 4x4ing. The D20 is a small case, it is gear driven, and there are many aftermarket gearsets and upgrades available for it.