Truck Automatically shifted into 4Hi

[driverman1]

I was stopped at a red light last night and I heard my 2000 EB expy shift into 4hi. I looked at the dash and sure enough the 4x4 light was on. So I turned the knob to 4hi and back to awd and it shifted out. Crazy anyone have a clue?

 

[BakerEdition]

might be the electronic switch down by the transfer case...the technical name for it escapes me right now, but im sure someone will chime in...

 

[71Rcode]

I posted about this a couple weeks ago -- http://www.expeditionforum.com/f42/4x4-dash-light-truck-4wd-switch-a4wd-18559/#post145600

Think we both need to replace our shift solenoid -- they are about $75 or so.