Jeep Driveline Jitters
This bulletin applies to 2011-2013 Jeep Grand Cherokee vehicles equipped with the Quadra-Trac-TRAC II 4WD system or two speed on demand transfer case. Owners may indicate that they have experienced a driveline bump felt during acceleration at about 10 mph, the SERV 4WD message appears and the vehicle shifts from 4WD to 2WD, and/or binding of the front driveline while turning on steep grades at about 3-5 mph.
A re-flash of the DCTM (drivetrain control module) is required.
Install a battery charger to ensure that battery voltage does not drop below 13.2 volts or exceeds 13.5 volts during the flash process.
Reprogram the DCTM with software release 13.03 or later. Clear all DTCs after reprogramming.