Defect summary
IN THE EVENT THAT THE PROPER PUMP ENGAGEMENT SEQUENCE IS NOT FOLLOWED THE "OK TO PUMP" INDICATOR LIGHT WILL ILLUMINATE WHEN THE TRANSMISSION IS IN A DRIVE GEAR.
Remedy
AN ELECTRONIC CIRCUIT AND MODULE WILL BE INSTALLED TO LOCK-OUT THE PUMP THROTTLE ON ELECTRONICALLY CONTROLLED TRANSMISSIONS IF THE CORRECT LOCK-OUT PROCEDURES ARE NOT CARRIED OUT.
Notes
SYSTEM: FIRE TRUCK WATER PUMPS.VEHICLE DESCRIPTION: FIRE TRUCKS WITH ALLISON ATEC ELECTRONIC TRANSMISSIONS,ALLISON MODELS HT741 AND MT648.CONSEQUENCE OF CONDITION: UNLESS THE TRANSMISSION IS PLACED IN THE LOCK-UP MODEBEFORE THE PUMP IS ENGAGED, THE ENGINE CAN DEVELOP SUFFICIENT POWER TO OVERRIDETHE TRUCKS PARK BRAKES, RESULTING IN VEHICLE MOVEMENT WITHOUT PRIOR WARNING ANDA POSSIBLE ACCIDENT.
Source: NHTSA ODI recalls file, campaign 91V124000. Text as published by NHTSA.