B. Operation During Electrical Interruption

B. Operation During Electrical Interruption

To minimize the impact of an electrical power interruption, 1000 and 2000 Product Families transmissions incorporate control logic that enables the transmission to revert to total hydraulic operation. In all cases, the hydraulic system provides a “limp home” mode, allowing the operator to drive the vehicle to a service location

If power is interrupted while the transmission is operating in a forward range, the default positions of the shift valves, the selector valve, and normally open A Trim Solenoid enable application of two clutches to maintain forward range operation (either third or fifth Range). If power is interrupted while the transmission is operating in reverse or neutral, the transmission defaults to or continues Neutral operation. The operator may turn off and restart the engine, and the selector will provide R (Reverse)/N (Neutral)/Third Range capability regardless of the range at the moment of power interruption.

Table 5–4 summarizes the default range the transmission will shift to in the event of an electrical interruption. Refer to Section 5–3 for a complete description of the hydraulic circuit during electrical interruption in any range.

Table 5–3. Operating Ranges During Electrical Interruption Range Obtained After Electrical Interruption for Manual Selector Position

Range When Electrical Interruption Occurs R P or N OD, D, 2, 1 R (without throttle) — N N R (with throttle) — N 5th** N N N N 1 R N 1* 2, 3 R N 3 4, 5 N N 5 Range After Engine Shutdown and Restart R N 3 * Third range after reverse is selected. ** Fifth range prior to N04 software or with throttle applied