Axle troubles Dana 30 HP

Okay I was having trouble with my 4wd not engaging, I took the vacuum thing off the front D-30 to find that the axles were not lined up, so that little thing that slides over and locks both axles together wasn't working. Well I fired up the Cherokee and put it in 4wd, jacked up the pass. front and moved it back in synch, slid the little thing over, then put the vacuum crap back on. Part-time light was working, and I drove it around a bit to see if it was okay, and it was. So I park, put it back in 2wd, then shift back to 4wd and got the same damn problem, it won't engage. What is the problem here??

You have to drive it a few feet for everything to line up!

mark

I did that too, it just won't engage, I tried to go real slow, maybe the vacuum thing that sucks it over there doesn't have enough pressure. It seems like it has plenty but as soon as I disengaged it, and tried to put it back in 4wd, same thing, refuses to go in.