Lately when (2000) Tundra is in 4WD there is a distinct vibration that you can hear and feel in the steering wheel. Pickup wants to pull to the left slightly or so it feels also when in 4WD. It engages fine, but vibrates above 10mph and when disengaging it doesn't want to, light will blink green and I've had to put it in reverse to get it to disengage at which point it bangs slightly. Any thoughts? I've changed the center diff fluid, and am planning on changing the front driveline U-joints...there were no metal shavings in the oil when I changed it fyi...any help would be great!

Just wondering if you have figure any thing out mine is doing the same thing