A utomatic transmission repair scam. The mechanic claims he/she cannot determine the cause of your car’s shifting problem until he tears the transmission down and then tells you it needs to be completely rebuilt at a cost of $500 to $3,000. As proof, he shows you small metal shavings in the transmission fluid.

Reality: Minor shifting problems are often caused by other, less-expensive problems elsewhere in the engine, and some shavings are normal.

Self-defense: Practice routine transmission maintenance. Have a mechanic check the transmission fluid and clean and replace the screen and filter regularly. Get two written estimates before approving any major transmission work.

Brake repair scam. After luring you in with a lowball $59 brake special, the mechanic tells you that your car needs a complete brake job. Cost: Upward of $500.

Self-defense: Get a second opinion. Get a written measurement of the pad wear, and compare this with what the owner’s manual says indicates a need for new pads. Avoid low-price service specials.

Coil spring repair scam. Coil springs, which help support the car body, should last the life of the car.

Self-defense: Ask for a written measurement of the distance between the ground and the bottom of the car. Reason: Unless it’s significantly less than what the owner’s manual says it should be, you don’t need new coil springs.

Body shop insurance scams. Body repairs paid for by insurance companies are often done with substandard parts, may be incomplete and might involve kickbacks, fraud and forced discounts to the insurer.

One problem: It’s difficult, if not impossible, to do such repairs adequately for what the insurance company will pay and so the repair shop cuts corners.

Self-defense: Insure your car with a reputable agency that will give you a choice of body shops. Compare the estimate to the final bill to make sure everything it said it was going to do was actually done.