Did you refill the front axle with 90w gear oil? It sounds like you drained the front differential and transfer case, but did not refill them. I'm not sure about the 7300, but on the 2710, there is a separate yellow dipstick/filler plug on the right side of the front axle. Failing to refill this would not affect the transmission, but would greatly affect the front differential, especially in 4wd. Perhaps it is running fine for now, but if this is the case, you are taking many hours of life off of the drivetrain for every hour you operate it this way. Maybe your manual was indicating that you should change the fluid for all of these locations, even though you need to fill different reservoirs when you are through. I hope I am all wrong on this one.
PaulT