NP229 Are they all the same?

We just purchased an 86 Pioneer w/ NP 229 and are having trouble with 4wd staying disengaged. I've read other posts - but not sure it's all the same(NP 229s) - new to Jeeps and this board, etc. Help - what should we do to find the problem?

ALSO - can disconnecting the shift rod from the vacuum shift motor be a temporary solution without causing any damage? It's in 2WD at the moment....HELP!

You'll have a hard time finding a lot of info on the old 229 transfer case. That was the optional Selec-Trac case used only from 1984 thru 1986. The factory service manual I bought for my '88 is actually the 1985 FSM with a bunch of additional volumes for the 1988 engine, tranny, and transfer case, so my FSM shows your unit. Unfortunately, I'm several thousand miles away from it at the moment so I can't look anything up for you.

I know there is a vacuum control function involved, but I don't know if it needs vacuum to keep it IN 4WD, or to keep it OUT OF 4WD. I would begin by checking all your vacuum lines.

Thank you! We've checked the vacuum lines and they are ok. I found a mode rod adjustment and we are going to check that out - also thinking it's possibly the selector switch. Is the NP229 the same in both FSJ and the Cherokee XJ? I've found lots of info for the FSJ NP229.