Shifts into low 4WD and shifts out of 4WD but still all 4 wheels seam to be pulling.

While vehicle is stopped - shift transmission into neutral - select 2wd - back up 10 feet. 4 WD shift problems are usually caused by lack of system exercise. Good idea to use it every once and a while - even when not needed.. Additionally - 4wd LOW is seldom needed - plus it requires specific shift sequence.