:welcome:
The recorded mileage is stored in the BCM. If the Dealer (GM?) replaced the BCM, they should have updated the mileage at that time. What was the mileage reading when you bought the truck? There should be an odometer reading on the bill of sale. I didn't think it was legal to sell a vehicle with the odometer inoperative. If it went "inop" after purchase, the replacement BCM may be defective.
The recorded mileage is stored in the BCM. If the Dealer (GM?) replaced the BCM, they should have updated the mileage at that time. What was the mileage reading when you bought the truck? There should be an odometer reading on the bill of sale. I didn't think it was legal to sell a vehicle with the odometer inoperative. If it went "inop" after purchase, the replacement BCM may be defective.