axle problem

Well I have an 88 cherokee with vaccum disconnect and just swapped the axle shaft to a full lenght shaft instead of the disco. The shaft came out of a 92 and now it seems that after i tried the 4wd it hasn't come out all the way. While driving at slow speeds i hear a constant thump like its still turning the front drive shaft. Can anyone tell me what it could be? Thanks in advance.

It is still turning the driveshaft. Once you put in a solid axle shaft, you have no disconnect any more, and the driveshaft will turn whether or not it is being powered. You can check that it's not actually in 4WD by jacking up a wheel. Leave the vehicle in gear, in 2WD. If you can turn a wheel, it's disengaged. If you can't, then it's not disengaging at the transfer case. But either way, if you have a bad u-joint in the driveshaft or other drivetrain problem it will make itself known now.

I thought that might be the problem but wasn't sure. It sounds like something is out of balance so maybe I'll start with new joints and install the other unit bearing I have off the shelf. Hopefully thats all it is cause my 93 doesn't make any noises like the 88 has now.