[XJNick]

Hi,

The noises form the front axle might be worn or bad U-joints.

As for the vacuum system... I believe having no vacuum will cause it to either stay where it is (engaged or not). However, it wont be held in that position by anything (no vacuum will be pushing or pulling on the vac. motor), so there is a good possibility that the shift fork could start to move and even get stuck. So I wouldn't recommend it unless you just do it once to verify if it's a vacuum probem or not.

Another possibility is that your transfer case linkage is not adjusted properly, and is slipping out of the 4x4 positions. You'll see a bolt on the linkage which is used to adjust it. Make sure this bolt is tight.

-Nick

	Transfer Case Mounted behind and driven by the vehicle transmission, the transfer case transmits power to the front and rear driveshafts in 4WD Jeep vehicles and offers high and low range.