Im having problems with my 4wheel drive and im not sure what it is. I'm not to good with these electronic transfercases and vaccume lines. When i press the 4hi button the transfercase makes its noise like its switching over and the 4hi button lights up, BUT does not engage the front wheels. So doing a little investigation i took my battery off and looked at the actuator. I jacked it up off all 4 wheels and pushed the actuator pin in and had somebody put it in 4HI, what do you know the front tires engage. SOOO this being said, could this narrow it down to be an actuator? or a vacume like or ANYTHING? Hope this info can give me an answere...THANKS!

 

Not sure if you've seen this very informative thread:
Common 4x4 Problems

You likely have a vacuum issue. Could be the vacuum supply to the switch in the transfer case, the switch itself, the line from the switch to the actuator, the actuator, or a combination of all of the above. You really have to get in there and assess those parts.

 

I was looking into my vacuum lines but did not trace them from my transfercase. I traced them from the ball thats under your hood that runs HVAC too...and i found a line that runs from that ball and up my tranny dipstick and stops? im not sure if thats supposed to be there. i learned alot from your thread and just need to take a better look at things now that i understand it. Thanks for your help!