2002 3.4L 5MT stuck in 4wd?

4wd light stays on, but with selector lever in 2H and the steering wheel turned all the way, there is no jumping around when I drive forward. When I put it in 4H with wheel turned, it definitely doesn't like it, behaving like every other 4wd vehicle I've driven.
With both front wheels off the ground, spinning one wheel does not cause the other to spin.
Can anybody tell me what's going on?
Everything I'm finding deals with an automatic transmission. I guess there weren't too many of these made.
And of course there are TWO actuators. I found the one in front of the year drive shaft, but didn't know to look for the other while I had it up in the air.
Anybody?

 

Sounds like your ADD is acting up. Common and lots of info floating out there on getting it unstuck, cleaning, banging free, removal...etc

I'm pretty sure your truck has vacuum lines to the actuator (ADD) - so I would first check all those to make sure they're viable. This would be good first step since the light isn't flashing on you - your truck believes it's in 4WD.

 

The ADD in the automatics has no vacuum lines, only breather lines. It's all electronic. I cannot confirm the same is true for the manual versions.

 

It sounds like your ADD (Automatic Disconnecting Differential) is acting up. This is not uncommon.

On your manual transmission and manual transfer case truck, there is only one electronic actuator, which is the one on the front differential. It is responsible for connecting and disconnecting the front CV axles to the differential. The lever inside the cab physically shifts the transfer case in and out of 4WD, and it also has switches built in, that tell the ADD when to shift in and out of 4WD. It's not uncommon for the ADD to become gummed up or corroded on the inside and stop working. It also has position switches on the inside that are used to turn on the 4Hi/4Lo lights.

When you jacked up the front of the truck and spun the wheels individually, was it in 2WD or 4WD? If it was in 2WD, then the ADD is working correctly but there might be an issue causing the light to stay on. If it was in 4WD while you turned the wheels individually, then the ADD is not working as it should.