It is likely the TFC is locked in 4X4 mode, why is the question.

On the auto 4WD models the front axle is not controlled by the vacuum switch on top of the transfer case, the TCCM uses a solenoid valve to engage and disengage the front axle. Removing the fuse likely kills the power to the solenoid, leaving the front axle disengaged.

The 3 button or lever models lock 4X4 Mode in like a standard transmission, a shift fork moves a collar mechanically coupling the chain inside to the main shaft driving the rear driveshaft. The 4 button auto 4X4 models use a clutch pack similar to one inside an auto transmission. When in auto it locks in the front axle and uses the 2 driveshaft sensor readings to determine slip, then uses the encoder motor to apply varying pressure to the fork inside the case that squeezes the clutch pack to engage 4X4 when needed. In regular 4X4 mode the front axle locks in and the encoder gives full pressure to the clutch. To keep the motor in position without constantly apply power to it, there is a brake assembly mounted on top of the motor. When the TCCM commands motor movement, it unlocks the brake, when the motor is not moving, it locks and the power to the motor is turned off. Removing the fuse would not let the motor run back to 2 wheel mode, it would stay wherever it was when the fuse was removed, assuming the brake is working.

 

Forgive me slimsummers, but I'm not very knowledgeable about all of this and I kind of understand what your saying. All I know is, when I take the 4wd Fuse out, it doesent matter if vehicle is off or already running, it will shift out of 4wd and into 2wd when I shift gears out of park. I can hear it.