on an allison doc is indicating number 3 solenoid valve stuck on and when the gear is engage to drive, it starts engagement in fourth gear and will never shift remains only in the same gear. Does anybody out there with an experience. Because we have check the cable connection, clean the valve assembly but the problem still persist. Allison type 2500PTS.
In the manual the limp home test is to unhook the main harness from the transmission, restart the unit and check for reverse (c-5 clutch) and forward (c-3 clutch) to limp unit home. Is it possible you have no voltage or communication to the transmission from the ECU and it is in limp home mode. Also check for faulty NSBU switch behind selector shaft.
allison gearbox
Posted - 04/06/2011 : 1:50:32 PM
