As often happens, I have 2 customers with near Identical Vehicals with
Truck #1: CPI (Vortech style) 4.3/Automatic.
No power at TCCM (Transfercase control module)
Power Key ON at TCCM Fuse.
Transfercase in High Range, Front axle unlocked.
Truck #2: TBI (Pre 1992 Style)4.3/Automatic
No Power at TCCM
Power Key On at TCCM Fuse
Front axle locked in for 4WD/ Will not unlock unless Vaccume line is
removed from Vaccume Servo (under battery tray).
When left with Engine running, Transmission in Park, Vaccume line on
Servo, can hear encoder motor trying to switch something.
My time to diagnose both vehicles is limited at current. At current I
don't have a decent manuial covering these transfer cases, controls and
trouble shooting proceedures.
Any one have any good advice?