I replaced them one at a time so I don't think that they are in the wrong location on the vacuum switch. It does pull the actuator some when 4wd is engaged so I believe that the lines are on the correct ports. It does also release the actuator when 2wd is selected.

 

What's to say the lines were on correctly when you replaced them? Check the routing in the first image. Make sure the vent line routing is correct. If the filter is connected to the actuator circuit, the actuator will not get full vacuum. Something is obviously wrong. Should show manifold vacuum in 4WD at the actuator with the engine at idle.

 

I gotcha. If I replaced them and I put them back to the way they were they could have been wrong to start with. I'll double check them. On the vacuum lines up by the fender there is a line that goes to inside the cab for HVAC. Is it a real small hard line (about 1/8" diameter)?

 

Is your front diff low on 80w-90?

 

Possum, you are correct on all counts.

On the left inner fender, the black rubber vacuum line changes to hard black plastic, (about 1/8" diameter). Pull the rubber line off and connect the vacuum pump directly to the plastic line. After checking for leaks on a particular mode, when you switch to the next mode position, the vacuum might deteriorate, (normal) and you'll need to bring it back up to ~18". Make sure each mode position test starts with ~18" of vacuum.

 

I applied vacuum to the line going to the actuator (from the t-case end of line) and it engages (by hand turning the wheel it rotates the drive shaft) at as low as 5" vacuum. The plug has 2 - 5/32" lines (1 for actuator and the other is for vacuum supply). The other line is 7/32". It was connected to the vent.
I have another vacuum switch here so I put the plug on the switch and applied vacuum to some lines that were only 6” long. I could not get the 7/32” to hold a vacuum with the ball in any position (vent line). I could get the 2 – 5/32” lines to hold vacuum together by pushing in on the ball of the vacuum switch (4 wd mode). The supply side would hold a vacuum with the ball in or out. The actuator line would only hold with the ball pushed in (with the ball not pushed in you can blow into the actuator line and it comes out the vent line (7/32”) (2 wd mode).
The 2 – 5/32” lines were reversed. I finally have 4wd.

 

Good, glad you figured it out. Thanks for posting back.

 

Glad to hear.