Transmission function is monitored electronically for abnormal conditions. If a condition is detected that could result in transmission damage, Transmission Limp Home mode is activated. In this mode, the transmission remains in FOURTH gear (for 68RFE transmission) or THIRD gear (for AS69RC transmission) regardless of which forward gear is selected. If an AS69RC-equipped truck enters Limp Home mode at highway speeds, it will initially engage FIFTH gear, until the vehicle slows to a speed where third gear can be engaged. PARK, REVERSE, and NEUTRAL will continue to operate. The Malfunction Indicator Light (MIL) may be illuminated. Limp Home mode allows the vehicle to be driven to an authorized dealer for service without damaging the transmission.
In the event of a momentary problem, the transmission can be reset to regain all forward gears by performing the following steps:
Stop the vehicle.
Shift the transmission into PARK.
Turn the ignition OFF.
Wait approximately 10 seconds.
Restart the engine.
Shift into the desired gear range. If the problem is no longer detected, the transmission will return to normal operation.
Even if the transmission can be reset, we recommend that you visit an authorized dealer at your earliest possible convenience. An authorized dealer has diagnostic equipment to assess the condition of your transmission. If the transmission cannot be reset, authorized dealer service is required.