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.