6.0 vs 7.3
The 4R100 has a 31 spline output shaft, and the 5R110W has a 34 spline shaft. The electric transfer case behind both is an NP273, so you should be able to split the case and change out the input shaft to match the 4R100 output. I don't think there was a difference in the front case half.
http://www.blueovaltrucks.com/tech/transfer_cases.htm
http://www.americanpowertrainwarehou...-s5-47m-24257/








