Abnormally high level of gearbox slip
Check the oil level in the oil sump.Contact an Allison dealer.
What you'll see
No driver-visible symptom recorded.
System reaction
The Allison fault code number is: P0894.The fault code is set when 1st gear is selected and turbine speed is higher than a calibratable value.The cause of this fault code can be: Incorrect oil level in the gearbox.A solenoid governor valve has jammed.The locking valve for C1 or C2 has jammed.Incorrect pressure control or shift solenoid.For the fault code to be set, the following conditions must be met: The hydraulic system is pressurised.No continuous default hydraulic conditions.No start up or shut down process of the engine in progress.The lock-up cannot be locked.The control unit shuts off gear changing adaptation.The control unit specifies 1st gear.While the fault code is active, the control unit ignores all information from the drive mode selector. The fault code is cleared automatically, when the vehicle has completed 40 start-up cycles without the fault being detected again.
Diagnostic depth
The turbine speed is higher than a calibratable value when 1st gear is selected.
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