GM does offer the encoder motor in both new and remanufactured for some applications, you might check with them to see if that is true for your Suburban, I'm starting to forget in some cases what is and what is not available and things do change as time goes past in the dealership availability world.

If memory is correct there was about a two hundred dollar difference between new and reman, same warranty though,12 months.

My wife's old suburban did that. Took it to mechanic and they unplugged the electrical connector to the motor. Plugged it back in and it shifted out of 4x4. Put some dielectric grease into the connection and it works fine to this day. Water and salt and grime got into the electrical connector and was shorting it out. Might wanna start there before it gets too expensive.