I don't know, if I am missing something. Presently I am trying too troubleshooting my 95 explorer 4lo. You need the vacuum actuator for 4wd to work. The 4 low gearing is inside the transfer case. The shift motor shift the lower gears in place. My question to you is. Is your 4 wheel drive system working? From my own experience when I set my explorer in 4low it stay there. Even when the vehicle (engine shut off and on) is turned off and on. You can turn your explorer into 4 low, go under the vehicle and disconnect the connector on the shift motor and will never shift out 4 low gearing.The vacuum actuator locks the front HUBs in place. You need vacuum too make it lock and stay locked. The 4 low system is a by product of the 4high system.The 4 high system has too work for 4 low to work.