Incorrect gear ratio on low gear
Contact an Allison dealer.
What you'll see
No driver-visible symptom recorded.
System reaction
The Allison fault code number is: P1739.The fault code is set when the vehicle is stationary and the calculated gear ratio differs from the actual gear ratio on low gear.For the fault code to be set, the following conditions must be met: The hydraulic system is pressurised.No gear changing in progress.No continuous default hydraulic conditions.No start up or shut down process of the engine in progress.The fault code is cleared automatically, when the vehicle has completed 40 start-up cycles without the fault being detected again.
Diagnostic depth
The actual and calculated gear ratio do not correspond to low gear.
This is probably caused by a mechanical problem, for example a problem with clutches C1 and C6 for low gear.