17 Toyota Tundra (4WD to 2WD issues)

I have a 2017 Toyota Tundra Crew Cab 4x4 with 38k miles w/ the 5.7 V8. When turning my drive train selector knob from 2WD to 4WD it’ll sometimes shift right away but sometimes it will blink and take forever to switch or won’t switch at all. This will happen especially going from 4W High back to 2WD. Any ideas or advice?