Need Help, 4x4 problems with my 1984 Sierra...

[LiftedNgeared]

Im just finishing up the installation of the motor on my 84 Sierra 4X4 that I just purcashed and the motor is working great but I have run into problems with the transfer case. I am only getting low range 4x4 and can't seem to get it out of that into two wheel drive.The truck is running fine and it drives in low range but I gotta get it into 2x4 but having no luck. Im tryin to make sense of this. The 4x4 shifter seems like it is stuck and won't go ahead any further and to get into two wheel drive the shifter should go further ahead towards the dash but it's back towards the seat. You can move it into neutral but no 4 hi or 2 wheel drive. The 4 wheel drive was working fine but the truck sat for a few months with no motor so Im really stuck here. Im just new getting into working on trucks as it's my first one and if someone could give me a hand it would be greatly appreciated. Thanks...