14584 - SERVICE UPDATE. REPROGRAM THE BODY CONTROL MODULE (BCM) WITH AN UPDATED TOP SPEED CALIBRATION ON CERTAIN 2015 MODEL YEAR CHEVROLET SILVERADO HD CREW CAB AND GMC SIERRA HD CREW CAB VEHICLES EQUIPPED WITH LIQUEFIED PROPANE GAS (LPG) / COMPRESSED NATURAL GAS (CNG) ENGINE (RPO LC8), 6-SPEED AUTOMATIC TRANSMISSION (RPO MYD) AND 4.10 GEAR RATIO REAR AXLE (RPO GT5). IF THIS CONDITION IS NOT CORRECTED, HIGH STRAINS MAY OCCUR IN SOME POWERTRAIN STRUCTURAL AREAS AND PROLONGED EXPOSURE COULD RESULT IN CASE FRACTURES OF THE TRANSMISSION AND/OR TRANSFER CASE, AND FLUID LOSS COULD FOLLOW.