EATON IS RECALLING CERTAIN EATON AND FULLER BRANDED MEDIUM DUTY AUTOMATED MECHANICAL TRANSMISSIONS, MODELS ULTRASHIFT HV WITH PARK FEATURE, PART NUMBERS FO-5506B-DMS, FO-6506B-DM3, F-5505-DM3 AND F-6505B-DM3, AND THE HYBRID TRANSMISSION WITH PARK FEATURE, PART NUMBERS EH-6E606B-CD, EH-6E606B-P, EH-6E706B-CD, EH-6E706B-P, AND EH-6E706B-UPG. THESE TRANSMISSIONS ARE SOLD AND INSTALLED AS ORIGINAL EQUIPMENT IN MEDIUM DUTY COMMERCIAL AND SCHOOL BUS VEHICLES. DUE TO AN ERROR IN THE INSTALLATION PROCESS, THE PARK FEATURE MAY NOT ENGAGE.