Manual Drivetrain and Axles Flashcards

A vehicle makes a clunk when shifting from drive to reverse, and the driveshaft shows movement at the U-joint. What is the most likely cause?

Answer: Worn U-joint needle bearings

Worn U-joint bearings create play that clunks when driveline torque changes direction.

A two-piece driveshaft vibrates at highway speed after a lift kit was installed. What is the most likely cause?

Answer: Incorrect U-joint operating angles

Raising the vehicle changes the driveline angles, and unequal or excessive angles cause cyclic speed changes that vibrate.

When reassembling a single-piece driveshaft with Cardan U-joints, how should the yokes at each end be positioned?

Answer: In phase (aligned in the same plane)

Keeping the yokes in phase lets the second joint cancel the speed changes created by the first.

A front-wheel-drive vehicle makes a clicking noise only while turning sharply and accelerating. Which part is most likely at fault?

Answer: Outer CV joint

The outer Rzeppa-type CV joint works at steep angles in turns, and wear there causes clicking.

A FWD vehicle shudders or vibrates during straight-line acceleration but not while coasting. What is the most likely source?

Answer: Worn inner CV (tripod/plunge) joint

A worn inner plunge joint causes shudder under load during acceleration.

While inspecting a CV axle, a technician finds a torn outer boot, but the joint is quiet and has no play. What is the best repair?

Answer: Clean, inspect, repack, and replace the boot, or replace the axle

Once a boot tears, dirt and water get in, so the joint must be cleaned and resealed quickly or the axle replaced.

What is the main purpose of the slip yoke on a rear-wheel-drive driveshaft?

Answer: To let the driveshaft length change as the suspension moves

Axle travel changes the distance between the transmission and the differential, and the slip yoke slides on the output shaft splines to make up for it.