2000 ZR2 4x4 issue
4x4 was not engaging. I found the vacuum actuator boot was torn, so I replaced it. 4x4 worked fine for about a month.
Hit switch to engage 4x4 high. Hear the transfer case motor engage. Accelerate the truck and hear click click click (not quite grinding) that increases or decreases with speed. Replaced vacuum switch on tcase and then replaced all fluids (front dif, t case, transmission) That seemed to fix it for a week. Back to making noise click click clck again when in 4x4 high. making noise but not actually engaging front axles. Ideas?