I had a problem with my 4x4 not engaging properly. It had getting worse and finally wouldn't engage at all. The mechanic disconnected the vacuum lines and found everything was working at the t-case and at the front axle. Then he discovered that the lines themselves were blocked with crud and had finally plugged up. It works great now. My question is: How did crud get into a supposedly sealed system? Has anyone else had this problem?
It's a 97 CTD club Cab with 160 km
Thanks, Bob

 

Most likely oil from the vacuum pump.

 

I had problems with mine engaging properly last year a couple of times. It has been working since then though. Was it a big job to clear the lines and how did he do it?
Matador

 

I had water git in during the winter (we plow with it, so snow gets everywhere). The boot right at the vacuum switch on the trans case was probably the culprit. It froze up the switch, so got a new switch and then the plug/boot didn't seal on the new one. So I figured that's where it got in at.

matador: just take the lines off and blow some compressed air into them.