So after trying several things to solve my 4wd issues (replaced the TCCM,encoder motor,vacuum lines etc) I have traced the root problem to the encoder motor electric brake not releasing.There are two leads going to the brake release in the 4 prong plug in going to the encoder motor.The brake works fine on the bench,but the signal that unlocks it is not showing up at the encoder,so the motor tries to shift,but can't rotate and kick the system into shutdown.The first time this happened was when trying to shift out of 4lo,but wouldn't. Long story short,I removed the brake assembly from the encoder motor and the system now works without the brake. I am considering reinstalling the brake and jumping the brake release leads to the encoder motor leads.That (in theory) would release the brake at the same time the encoder motor starts and lock the brake when the motor shuts off. This may not be a long term fix,but the 4wd works now and that is what I was looking to accomplish.The only issue I have seen with the current setup is when shifting back to 2hi from 4hi,the case sometimes ends up in neutral but the case shifts back into 2hi on it's own if you shut it off and restart.

 

I know in he diy tech section around here there is a lot of info on the 4x system....i know thats not a direct answer....but it may help ya