New here so thanks in advance. Have a 97 Sierra 4wd 5.7 with a np 243 transfer case, electronic shift. Truck will not shift in and out of 4wd. Light shows 4wd low but is not in low 4wd. When you try to switch to 4wd high u can hear the tcm click and it just flashes and goes back to a solid light 4wd low. Have tried putting in neutral in a slow roll to change as suggested. Encoder motor just clicks/ cycles (even with the ignition off and key out? All fuses are good, encoder motor is new, tcm is new , ecu is new , switch on dash is new , front diff acuator is new and all fluids are full. The only thing not replaced are the speed sensors. The parts cannon has been fired! Anyone had a issue like this or any ideas?

 

When did you first notice the problem?

 

did you find the issue ?