QUICK ANSWER

• A high-pitched squeal under braking is a wear indicator doing its job — book it, don't wait for grinding.
• A slow or labored crank at startup is a battery or alternator warning, not a random cold-morning fluke.
• A clunk over bumps, especially on a lifted Jeep with larger tires, points to suspension or drivetrain wear.
• A rhythmic click that speeds up with your speed usually means a wheel bearing or CV joint.
• None of these need a dash light to be worth booking — the sound is the earlier, cheaper warning.