How do you know if you need shims on a starter?

You might need shims on a starter if you experience difficulty starting your engine, unusual noises during cranking, or if the starter gear does not engage properly with the flywheel. Additionally, if the starter is misaligned or if there is excessive wear on the starter drive or flywheel, shims can help achieve the correct alignment and spacing. It's important to check the manufacturer's specifications for your vehicle to determine if shimming is necessary.