Things never stop. So the transfer case I swapped onto my 03 locks up fine, but won't shift high-low range. The linkage is new and a cable type. It was suggested I remove the actuator from the top of the case to see if it's siezed but I can't see a good way to get enough access to do this... any other ideas? It would really suck to have to swap the case out again.

 

I just went through this with my 03. The actuator you refer to is a locking solenoid, safety device to keep you from shifting to low while in gear. It would really help if you had a lift to use to raise the vehicle up head high to work on. First thing is drop the rear drive shaft, not hard just a few bolts. Second take off the emergency brake from the transfer case. By doing this you should have plenty of room to reach up and remove the bolts holding the case that surrounds the solenoid. Personnally I just removed the solenoid and threw it away. Its just something that could mess up later. Just be careful not to try and shift from high to low while cruising down the interstate. The solenoid is located in the front right on top of t-case. Its a small round raised area. This will require you to glue the gasket back on when finished.
Hope this helped.

 

What about the solenoid in the 04 shifter lever I put in? Could that one be the culprit? Would be easier to remove / bypass for sure.

 

You bet it could if thats easier then go for it first!