I’m not 100% sure but I believe your transfer case has a sensor built into it that tells the computer when the wheels are turning but vechial speed doesn’t match. Which in turn makes the computer think your in sand, mud, etc. and that engages the auto 4 wheel drive. I don’t know why it selects low verses high 4 wheel drive. That in its self is possibly a clue? Your truck might even use the antilock breaking wheel sensors to accomplish this. The reason I say this is the fact you said you have to turn off the truck and then back on, basically resetting it for a time. So your probably looking for a intermittent connection issue so check all of you wheel sensors for good connections and any wiring that might have rubbed and exposed the actual conductors to water. Also make sure the transfer case wiring harness connection point is dry no water in were the pins make the contact. Try to be aware of any external conditions, such as weather related, it’s cold, it’s hot, it’s raining. To see if a pattern of acting up shows itself. Everything is a clue when dealing with a intermittent issue. Even the frequency of when ( time from starting the truck until you have a issue.) And the frequency of how many days between issue. Are clues to finding out the real cause. I would lean into the sensors because there are a few of them needed to make this auto 4wheel setup to work, they are on the external outside of the vechial, they all need good dry electrical connections at consistent ohms or voltages to tell the computer how to work,
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