does it have vacuum hubs? and how i test vacuum valves is use a long vac hose connected t engine manifold vac start engine and test. if a solenoid test power and ground ez if you put a test light between the terminals. just for fun look under hub caps for a disconnect
Fixed on my own a while back: Replaced 4WD Gear next to front diff. No vacuum system. Vehicle since sold and replaced with 2015 DA16T.
