Hey I'm new here. I have a 01' auto 4wd xterra. Winter has just started near me so I haven't used 4WD in a while. Recently had a snow storm and needed to use 4wd to get around. When I switch back into 2wd after using 4wd it vibrates at around 45mph and also 55-65 mph. So it vibrates while in 2WD after at higher speeds and in 4WD when using it. The vibration goes away after not using 4wd and staying in 2WD for a while. The other day when it was vibrating I parked it and switched between the transfercase gears. I then left it for about 20 minutes started it and she drove fine no vibrations in 2WD at all. What could be the issue here? It's related to the 4WD because I noticed no vibrations prior to this. I'm no mechanic any advice would be great. Plan on bringing it to my mechanic soon just wanted to get an idea on what the issue might be. Thanks.