I have a 2000 Blazer with a 233 transfer case (3 button switch). My question is how hard (or easy) should it be to move the fork that the actuator cable pulls on.

 

The shaft for the fork only moves about 1/4", is this what the total movement should be?

 

Yes it is

 

The shift fork should move real easy provided the diff and axle are lined up.

 

My actuator has vacuum to it but it does not seem to pull hard enough on the shift fork to drive the axle. If I pull on it manually it does engage the axle. It does not seem like I pull too hard but the actuator does not pull it far enough. The cable and actuator are new. I have already replaced all of the vacuum lines (they were in real bad condition). I have about 20" of vacuum (250K miles).

 

So how does someone check the alignment of the front axle to differential? I suppose that there is some kind of adjustment? I was thinking that the fork may be just gummed up? I know that when I did pull the fork that it does lock/engage the axle to the front drive shaft. I did notice that when I let go of the fork that it did not go back in until I rotated the wheel in an opposite rotation a little bit. I’m thinking that I will probably have to remove the half shaft to check for gumming/broken parts. Sounds like a pain in the…

 

There is no alignment of the front axle to differential, it just bolts together. Everything with engagement and disengagement that you described is normal. Could very well be low vacuum to the actuator. Pull the vacuum line off the actuator, and install a vacuum Tee in the line. Install a vacuum gauge to one leg of the tee. Connect the actuator to the remaining leg of the tee. Start the engine and select 4WD. Make a note of the vacuum reading. Shut the engine off. Does the vacuum on the gauge hold, or drop off?

 

My guess is there is a hole in the accumulator, they aren't getting any younger and like to dry rot with time.

 

I checked vacuum at the actuator. Found no measurable reading on the gauge but the actuator does pull a little bit. Previously replaced the actuator, all vacuum lines and the vacuum switch at the t-case due to transmission fluid in them (seal from transmission to t-case has been replaced). I checked vacuum at the vacuum switch plug and had about 17". So either the new line from the vacuum actuator to the vacuum switch on the t-case is kinked or has a whole in it or possibly the new vacuum switch is bad (is this correct thinking)?

 

Could be, but it could also be that the lines are not in the correct position on the vacuum switch.