Downshifting

108SD d 13.01.003

Important:  Never use the clutch brake when downshifting, or as a brake to slow the vehicle.

  1. To downshift from 8th overdrive to 8th direct (or 8th direct to 8th underdrive on RT model transmissions), move the splitter-control button to the low (rearward) position, then immediately release the accelerator. Press and release the clutch pedal, then accelerate the engine once the transmission has shifted.
  2. Start the downshift from 8th direct to 7th overdrive by moving the splitter-control button to the high (forward) position, then immediately double-clutch through neutral, moving the shift knob from 8th gear to 7th gear.
  3. Downshift progressively through each of the high range gears, alternating the procedures in steps 1 and 2 above until reaching 5th direct.
  4. When in 5th direct and ready for the downshift to 4th (13-speed transmissions) or 4th overdrive (18-speed transmissions), push the range-preselection lever down and move the splitter-control button to the high (forward) position. Double-clutch through neutral and into 4th gear, engage the clutch, and accelerate the engine.
  5. Continue downshifting from 4th gear to 1st gear.
    For 13-speed transmissions:
    Downshift through the low range gears as conditions require.
    For 18-speed transmissions:
    Continue downshifting from 4th overdrive to 4th direct, then 4th direct to 3rd overdrive, etc. Double-clutch during knob shifts (4th to 3th, etc.); single-clutch during split shifts (4th direct to 3rd overdrive, etc.).
Note:
Parent topic: Eaton Fuller 13-Speed and 18-Speed Splitter and Range-Shift Transmissions
Document Number: 0000111680
Manual Publication Date: 2024-09-03
Topic Publication Date: 2024-05-02