2009 GMC Truck disconnecting electric speedo "o'k&qu

Federal law would require you to grab your eldest son and place him under citizens arrest and hand him over to the proper authorities, just kidding, I don't think it's that easy just to disconnect the Speedo sensor, did you take the mileage down before he left? How far did he travel? Usually when you disconnect the Speedo sensor you will lose transmission simultaneously so I don't think he went very far with the speedo sensor disconnected, do you have an engine light on now? You may have to take it back to the dealer and have him we set the parameters on the transmission don't tell them what your eldest son did, you will probably lose your warranty if you do.