Ok so I followed the tips on this forum, I do have partial vacuum on the 4wd actuator under the battery tray even when in 2wd. So that means the electric controlled vacuum valve on the firewall behind and under the distributor is leaking. I can get the part of Ebay for $40 but just how do you get to the damn thing to change it out. Looks like from the picture it just clips to the firewall.

I think this must be a piece they put on before the engine goes in at the factory.

I was suspecting a blinking indicator if I tried to shift. With the vacuum plugged off I can select 4wd and the light comes on steady, but 4wd is not engaged. So I suspect the rotary encoder is going to position for 4wd telling the electronics it is happy but the mechanical link is not driving the wheels. Seems like an overly complicated system, but perhaps it is needed when push button 4wd is wanted.