Attempted to shift out 4-wheel high back into 2-wheel drive. On the dashboard, both 4 wheel high and 4-wheel low were flashing yellow/orange. Put truck into park to clear, nothing continued to flash. Put truck into neutral, nothing continued to flash 4 high and 4 low. Turned the truck engine completely off and started again. Both 4 high and 4 low continued flashy. Put truck into drive, 4 low and 4 high now became a solid orange/yellow, no flashing. Drove truck a mile and a half down the road and lost complete control of the steering. Ended up in ditch with several thousand dollars of damage. Contacted dealer where purchased. Explained what happened to the Manager of Toyota service department. He claims it has happened on other Tundra's, says it happened on his truck. Offered no explanation or fix to the problem.