I have a 1995 LS 4x4 4dr, with electric pushbutton activated 4x4. The buttons work fine, it will switch from 2hi to 4hi to 4lo, it makes a clunking noise when switching into 4lo. It runs in low gearing when in 4lo, but the front two wheels don't move. Ive checked the front wheels by jacking up the car, switching it into 4lo, and spinning the front wheels, they spin freely.

I'm heading home for 4 days next wednesday, I'll then have the help of my dad and all his tools to help me diagnose the problem. Any ideas of what i could do to try and narrow down the culprit?

 

Most common problem which has been covered many, many times already. You need to check if you are getting vacuum to the front axle actuator which is either on your passenger fender or under your battery. If you have vacuum there, then you need to make sure that it is pulling on the front axle engagement cable which runs down to the front diff.

 

In my '97 it was a loose vacuum line to the accumulator (ball-shaped thing) under the hood. If the line falls off, you lose vacuum. Check it - the price is right.