From what I learned at the Ford training class the flashing six is not a code. For some reason that is the number of times it flashes when a problem arises. The only way Ford gives you access to codes is with a scan tool. With the scan tool you would need to access the gam module to get the codes. You sound like you are knowlegable about the system knowing the Gem is part of the 4X4 system. I have just replaced a gem this week for the 4X4 lights flashing and it took care of the problem. Depending on your code that is retrieved there is a TSB from Ford. The tsb # XXXXX XXXXX I will try to paste it at the end. This tsb, depending on codes, gives possibilites of shift motor (which I have done many of), Speed sensors in transfer case, Wiring harness. I have also seen corrosion in the connector under the drivers seat. I hope this helps you out.
The 4X4 indicator lamps may flash on some vehicles. This may be due to oxidation buildup and/or premature wear on the sense plate of the shift motor which can send incorrect signals to the 4X4 controller. Terminals on the transfer case connector may also develop a resistive film, leading to faulty signals to the 4X4 controller.
Install a new shift motor and/or speed sensors with new terminal material. Refer to the following Service Procedure for details.
2. Use procedure 2 if:Binds in turns after startup in 4auto, if any of DTC's P1836, P1837, P1874, P1875 are present. This indicates speed sensor circuit failure.
3. Use procedure 3 if: There is no shift motor movement present, Any of of dtc's P1838, P1846, P1850, P1854, P1858, P1866, P1867 are present. This indicates a shift motor circuit failure,
4X4 lamps flashing with no DTCs stored in the GEM. Perform following repair procedure:
For 4X4 lamps flashing with one or a combination of DTCs P1836, P1837, P1874, and P1875 stored in the GEM, perform following repair procedure:
Replace all speed sensors with resistance less than 1,000,000 (1.0 Mega) Ohm. Service part numbers for the new speed sensors are: XL2Z-7F293-BA (front speed sensor) and XL2Z-7F293-AA (rear speed sensor). Proceed to Step 3.
For 4X4 lamps flashing with one or a combination of DTCs P1838, P1846, P1850, P1854, P1858, P1866 and P1867 stored in the GEM, perform the following repair procedure:
Resistance less than 1.25 Ohms is considered "Closed". Resistance greater than 5100 Ohms is considered "Open". If the resistance on any one of the contact plates is between 1.25 and 5100 Ohms, replace the shift motor. Also, if the resistance check on the shift motor contact plate A, B, C, and D DO NOT correspond to "COCC" in 4X4 AUTO and "OCOC" in 4X4 LOW, replace the shift motor with a new Transfer Case Shift Motor (XL2Z-7G360-AA). Proceed to Step 3.
Eligible Under The Provisions Of Bumper To Bumper Warranty Coverage
203000, 204000, 204100, 205000, 206000, 506000, 508000, 597997, 608000, 610000, 703000