Automotive Drive Axles

1. Automotive Drive Axles Constant Velocity (CV) Types

2. Drive Axle Components (fwd)

3. Drive Axle Components (rwd)

4. Outer CV-joint Allows wheels to steer while axle is rotating

5. Inner CV-jointAllows for suspension changes while axle is rotating

6. Axle shaftTransmits power from inner to outer CV-joint

7. ABS Speed Sensor Some axle shafts have an exciter ring welded to the outboard CV joint for ABS operation. During removal and service of this style of axle extreme care must be used not to damage or move this ring.

8. Drive Axle Components • Outer CV-joint • Allows wheels to steer while axle is rotating • Inner CV-joint • Allows for suspension changes while axle is rotating • Axle shaft • Transmits power from inner to outer CV-joint

9. Front Wheel Drive Issues With the engine mounted transversely, the transaxle sits to one side of the engine compartment. Thus, one axle must be longer than the other.

10. Front Wheel Drive Issues

11. Front Wheel Drive Issues Torque Steer - occurs when the CV joints on one drive shaft operate at different angles from those on the other shaft. The joints on the longer shaft almost always operate at less of an angle than those on the shorter shaft. With an open differential the shaft with the least resistance will receive more torque.

12. What? 1. A longer shaft will flex more thus being more forgiving at its outer angles. 2. A longer shaft will operate at more of an angle thus reducing the angles of the joint.

13. Front Wheel Drive Issues When the differential sends power to the wheels, the longer shaft will have less resistance because the CV joints are operating at less of an angle. Most of the engines power will be sent to that side. This phenomenon results in what is called torque steer.

14. Torque Steer Remedies Add an intermediate shaft

15. Torque Steer Remedies Vibration dampers - Sometimes used to stabilize the shaft as it spins.

16. Torque Steer Remedies Unequal length half-shafts - Usually constructed differently to reduce torque steer.

17. Types of Drive Axles • Equal length shafts • Used to reduce torque steer • Vibration dampers • Sometimes used to dampen vibrations in the driveline • Unequal length half-shafts • Usually constructed differently to prevent torque steer

18. Front wheel drive shafts turn at approximately 1/3 the speed of rear wheel drive shafts. Why?Benefits?

19. CV-Joint Types • Outboard joint • Does not move in and out to change shaft length • Fixed joint • Inboard joint • Changes in length to allow movement of the suspension • Plunging joint

20. Outboard Joint Movement

21. CV-Joint Types Inboard Joint Movement

22. CV-Joint Types

23. CV-Joint Types • Ball-type CV-joint • Was named after its designer, A.H. Rzeppa • Uses three to six steel balls held together by a steel cage • The balls ride in a socket to allow rotation and turning • Is used in most front-wheel-drive vehicles

24. Rzeppa Joint - Exploded View

25. Rzeppa Joint - Exploded View

26. CV-Joint Types Outboard Joints (cont’d) • Tripod-type joint • Uses a central hub (tripod) with three trunnions • Has roller bearings that ride on the trunnions • The outer surface of bearings ride in the joint or “tulip” housing • Allows for greater angles

27. Tripod Joint

28. Outboard Joint Movement

29. Inboard Plunging Tripod

30. Inboard Plunging Tripod

31. Inboard CV Joints • Ball-type (Double-offset) Joint • Is similar to a Rzeppa joint but has elongated grooves in the inner race

32. Inboard CV Joints • Tripod-type joint • Has longer grooves than a fixed-type joint to allow for plunging.

33. Inboard CV Joints • Cross Groove CV Joint • The grooves in the outer race are cut at an angle to allow for better movement.

34. CV-Joint Types Inboard Joint Movement

35. CV-Joint Types • Outboard joint types • Rzeppa fixed tripod • Inboard joint types • Double-offset • Plunging tripod • Cross-groove plunge joint

36. CV-Joint • All CJ joints have a rubber, plastic or neoprene boot to protect the internal parts. • The boots are fastened by clamps at either end. • All CV joints must be lubricated. • CV joint grease differs from standard wheel bearing or chassis grease. They cannot be interchanged!

37. CV-Joint • Constant velocity joints are called as such because they are designed to transfer a uniform torque and a constant speed through a wide variety of angles.

38. FWD Wheel Bearing Styles • Double-row, angular-contact bearings • Are used on most General Motors, DaimlerChrysler, and European cars • Have two rows of ball bearings located next to each other • Opposed tapered-roller bearings • Are used on Fords and most Asian cars

39. FWD Wheel Bearing Styles • The axle nut not only secures the end of the axle but it also sets the wheel bearing pre-load.

40. Diagnosing CJ Joints & Axles Bad CV joints will generally make a clunking or clicking noise. Outer joints will make noise on turns.

41. Diagnosing CJ Joints & Axles Bad CV joints will generally make a clunking or clicking noise. Inner joints will make noise over bumps.

42. Perform a Road Test • Drive the car under various conditions such as accelerating, coasting, turning, and weaving side to side • Listen for clicking or clunking, especially while turning • Feel for shudder, shimmy, vibration, or any other abnormalities

43. Diagnosing CJ Joints & Axles • Do not confuse CV joint noises with outer wheel bearing noises. • CV joint noises will be more noticeable at slower speeds. • Wheel bearing noises will have a higher pitch grind or whine. They will also be more noticeable at higher speeds on turns.

44. Visual Inspection • Check out all other problem areas before assuming that the problem is being caused by the axle assembly • Check the CV-boots for tears and grease leaks • Check the shafts for damage or being bent • Move the shaft, wheels, and other components to check for looseness

45. Visual Inspection

46. Possible Reasons for CV-Boot Failure • Cuts or tears from foreign objects • Accident damage • Improper towing hook-up or service techniques • Ice forming around boot • Deterioration • Clamp failure

47. Off-Car Axle Inspection • Be careful not to overtighten the shaft in the vise • Look for cracks, chips, pits, or rust on all components • Check the joint for sticking while plunging it in and out • Check for discoloring usually caused by heat

48. Boot Replacement Tips • Mark the location of the joint to the shaft • Inspect the grease for contamination • Make sure the new boot clamps are secure • Use a dull screwdriver to remove trapped air from the boot

49. CV-Joint Replacement Tips • Clean the joint thoroughly so a complete inspection can be made • Refer to the service manual to find out how the joint is retained to the shaft • Pack the new joint using all of the lubricant supplied

50. FWD Wheel Bearing Inspection • Excessive play inspection • Usually checked by pulling outward at the top of the tire and pushing inward at the bottom with the vehicle supported under the control arm • Noise inspection • Bearing noise will often increase when the vehicle is turned