Transfer Case 2 Speed drop Box and 4x4

I have a tractor with a Detroit 4-71 in it and the transfer case sits behind a Fuller 5 speed--Divorced----.. The Fuller 5 speed goes into a transfer case that has a HI LOW and 4x4.
QUESTION My transfer case is bad and down for the 3rd. time. What would I have if I installed a transfer case without the HI LOW---Just a one speed case, but would need it to operate the front axle in 4x4. Also do they make them to disengage the 4x4 without the HI LOW function.
What would I have for Power and road speed?????
Thank you for any help suggestions..........Maybe a transfer case out of the older Steigers in place of the one I have...........
lenray777@gmail.com