Ok, let me expound a little on what nccaveman said. What is happening is that both of your wheels are getting power. However the inner wheel travels less distance. The binding you feel is the wheel trying to travel farther than it's path allows. For this reason you should not use 4 wheel drive when driving on good, dry surfaces. It will eat tires, bind the drivetrain and cause more wear. On the FJC it will cause your CV joints to wear out quicker.
(Hard-core off roaders have switched out the front diffrerential config with straight axles.) When you are driving on wet surfaces (snow or mud) your faster wheel slips and you don't feel the bind. These stock differentials, both front and back are locked while in 4WD, which means in basic terms, you get power to all wheels instead of one wheel stopping altogether and the other wheel spinning like mad. Locking differentials make both wheels spin at the same speed and do not allow any compensation in relation to wheel-to-axle ratios. Anyway what you feel is normal, and will be beneficial when off-roading, but not on dry pavement.
Did I make sense this time? Sometimes I babble...
