do you have the auto trac trans case?
i think the 233 is the same as a 231 which is what i had just an electronic version, but the spline count may be different.
My '96 S-10 Blazer had a NP231 in it, and we ended up putting that in my friend's rig ('01 S-Blazer) in place of his NP233...direct swap in with a hole of 2 in the floors to allow the shifter cable to come through and we got creative to get my OEM floor shifter in his.
No clue what a np236 is out of, but I'll bet it's electronic engagement as well (junk).