General Information, Allison

SD DM 14.00.01

HD-series automatic transmissions have six forward speeds and one reverse speed. See Fig.. These transmissions have electronic shift controls that can be programmed to allow the use of different numbers of geared speeds. For instance, the transmission can be programmed to operate as a 4-speed, 5-speed, or 6-speed unit in the "primary" shift mode. If needed, a "secondary" shift mode can be programmed to provide another shift configuration to optimize vehicle use under different operating conditions. To activate a secondary shift mode, or other special function programmed into the electronic control unit (ECU), depress the Mode button. "Mode On" is displayed in the indicator panel just above the push buttons. A label just above the Mode button identifies the special function.

  1. Indicator Panel

  2. Mode ID

Fig. 1, Allison Push Button Shift Selector

Note: Each time a push button is depressed on the shift selector, a short beep will be heard. This indicates that the ECU has received input to change operation.

Note:
Parent topic: Allison Automatic Transmissions
Document Number: 0000123405
Manual Publication Date: 2025-01-23
Topic Publication Date: 2025-01-23