GM Service Manual Online
For 1990-2009 cars only

Your vehicle odometer is tamper-resistant. You may wonder what happens if a vehicle has to have a new odometer installed. If possible, or when regulations require, the new one has to be set to the same reading the old had. If it can't be, then it's set at zero, but a label on the driver's door must show the old reading and when the new one was installed.