1. Locate the vehicle identification number (VIN). The VIN is a 17-character code that can be found on the driver's side door jamb, on the dashboard, or on the engine block.
2. Once you have the VIN, you can use a VIN decoder to find out the rear end gear size. There are many free VIN decoders available online.
3. Enter the VIN into the VIN decoder and click "decode". The rear end gear size will be listed under the "drivetrain" section.
The most common rear end gear size for a 1997 K1500 is 3.73:1. However, some models may have different gear ratios, such as 3.42:1, 3.55:1, or 4.10:1.