New Freightliner Cascadia and M2 PLUS/SD PLUS - "Transmission Service Soon" notification screen

Applicable Vehicles

New Cascadia with an Allison 3000 Series or 4000 Series automatic transmission.

Business Class M2 PLUS or SD PLUS with an Allison 3000 Series or 4000 Series automatic transmission and an ICUC instrument cluster. (PLUS series trucks use the CEEA+ electrical architecture. This solution does not apply to M2 or SD trucks that use a Bulkhead Module.)

3000 Series and 4000 Series transmissions in these vehicles may use a right stalk switch (standard equipment), or an Allison pushbutton shifter (optional equipment), as the shift control mechanism. The right stalk switch is the standard-content shifter.

This solution might also apply to M2 PLUS or SD PLUS chassis with an Allison 1000 Series or 2000 Series transmission.

Symptoms

At engine start, a blue-bordered screen with the message "Transmission Service Soon" comes up in the instrument cluster for a couple of seconds, and then disappears. A picture of the screen is attached.

Issue

DTNA uses two different shift controllers with Allison 3000 Series and 4000 Series transmissions on trucks using the CEEA+ electronic architecture:

• the right stalk switch (standard equipment), which has no display capability and relies entirely upon the instrument cluster for display of information to the vehicle operator; and
• an Allison pushbutton shifter (optional equipment), which includes a gear display and has a Transmisison Service indicator (wrench icon) between the digits of the shifter display.

The Transmission Service Soon notification screen exists because Allison Transmission required the instrument cluster to provide warnings similar to the display in the pushbutton shifter.

DTNA does not configure the instrument cluster for the type of shifter installed in the vehicle. Therefore, for vehicles equipped with an Allison pushbutton shifter, the cluster provides a duplicate display of information that is shown on the display of the Allison pushbutton shifter.

The Transmission Service Soon notification screen displays in the cluster at engine start because Allison Transmission performs a bulb check if the Prognostics feature is enabled in the transmission calibration. On a truck equipped with an Allison pushbutton shifter, the message in the cluster display will be accompanied by the Transmission Service lamp (wrench icon) turning on in the pushbutton shifter display.

When displayed only at engine start as a bulb check,the Transmission Service Soon notification screen does not indicate that there is a need to service the transmission. Drivers, owners, and dealer technicians have expressed concern that the screen is being displayed.

If the display remains active or comes on while driving, then there is maintenance needed soon. This notification is the transmission controller's method of notifying the driver.

Solution

It is possible to eliminate the bulb check by disabling Prognostics using Allison Doc software. Allison Transmission indicates that Prognostics can be disabled without affecting operation of the transmission.

If Prognostics is disabled, the Transmission Service Soon notification screen will only be displayed when requested by the transmission controls when maintenance is needed. 

Disabling Prognostics may disable certain additional information screens on the instrument cluster. These screens contain information that may help a vehicle owner better understand how the transmission is being used.