Underbody Automotive Technology

A transfer case drives the front wheels via a chain and gears, turning the front differential; when worn, it may whine or rattle, and inspection can be dangerous.

Inspect u-joints for rust, looseness, and noise by checking for orange dust, testing play with hands and a pry bar, and inspecting caps; diagnose vibration or clunking during acceleration.

Explore sway bar links and how they control body roll during cornering, helping wheels stay tracked to the road and improving handling and safety.

Inspect the suspension springs for damage, especially if the vehicle leans to one side, and replace worn parts like load spring buffers or Jones pads to prevent bottoming out.

Identify rear toe issues by feeling for back-and-forth movement across the tire. Check rear toe during alignments and inspect the rear camera to prevent tyre wear.

Check upper ball joint play by feeling for movement, or with a partner. Sometimes you won't see it on all vehicles, and don't confuse it with a wheel bearing.

Learn to check lower ball joints by lifting at the spring on a solid surface with a pry bar to test movement, and jack on the unibody for accuracy.

Find tips for wheel bearing replacement, including dealing with corroded threads, using heat or an air hammer, and removing the rotor and caliper to access the bearing on the knuckle.

Learn how to use torque sticks to secure wheels on aluminum rims at 80 foot-pounds and steel at 100 foot-pounds, using a three-pass star pattern and watching the spring-loaded ball.

Identify the eccentric alignment nut on the control arm and learn to mark components before suspension changes to preserve alignment; rely on a professional shop for precise, cost-saving alignment.

Inspect the muffler for holes, tears, and rips, and look for black spots or sooty buildup to spot exhaust leaks that cause a noisy exhaust.

learn how to check for bad suspension bushings, especially front, rear, and lower control arm bushings, by testing movement on a solid surface and inspecting rubber for cracking.

Learn to check rear lateral links on vehicles, using the same push test as the upper ball joint: push at the top, bottom, and sides, and inspect every tire.

Jack up the vehicle, wiggle the tie rods to test play in the inner and outer joints, and feel for play to confirm wear.

Identify wheel bearing issues and differentiate them from ball joints by testing top-to-bottom and left-to-right movement with your hands, then spin the tire to detect noise, vibration, and brake condition.

learn practical ball joint replacement tips, including using penetrating oil, heat, and controlled hammer techniques on the control arm, with cautions about pry bars and bending parts.