Having problems with 4x4 engagement. got 181k miles on truck. Changed the
4x4 actuator and harness 2-3 years ago at the shop. For same problem. When putting the lever from 2wd to 4x4 hi or low 70% of time it will engage. The other times it will not. The indicator light goes on but actual engagement does not accrue. The indicator light flickers when accelerating. This problem is most prevalent when OAT is cool @ 34 or lower. Some one once said check the floor lever linkage as it might be gunked up???/