Need information for removing the transfer case from 1hz105 manual

While I've not pulled one of that model apart they would be similar to the earlier models.
I think you will now have to separate them to ensure seals and gaskets between the two are intact and can seal when assembled.
On the earlier and 75 series you had to remove the rear cover on the transfer and undo the nut on the end of the main input shaft from the gear box, then remove the gears and stuff on that shaft and then there are a couple of bolts between the transfer into the gearbox to undo and then they will separate ok. As they say reassembly is the reversal of the process with attention to wear on components like thrust races, bearings and seals. also check the main input shaft splines for wear.
Best to find a workshop manual to make sure or someone else might post.

Mathew
As Peter has mentioned above, just undoing bolts will not solve the issue at all. Familiarizing yourself with how it is internally constructed/assembled would have been a good idea before starting the job. The top gearing does have to be removed after shaft nut removal etc, because the gear arrangement will not go through the front opening no matter how hard you try. You may have to temporarily rebolt it so the shaft nut mentioned can be removed. Then take out the necessary bits and THEN remove the transfer case.

The last gear box I pulled apart was out of a Courier. You'd take all the bolts out, but there was also a roll pin on one of the selector shafts that had to come out.
To get to that there was a cover plate that had to come off to access the roll pin.

From how you describe the coming apart 1/2" and locking, it was exactly what mine was doing. How to access it, I have no idea.

It would be a good idea to take it apart and inspect the seals though.
On the old 40 series models, they had a habit of leaking the gear box oil into the transfer case (or the other way around) through a dodgy oil seal that could leave one side way over full and the other running dry.
I have seen some cobbled together fluid leveling devices plumbed in to the filler plugs so you didn't have to split the cases and replace the seal as the two would equalise, but not having the issue in the first place is probably the better option.