Drivelines

1. Drivelines

2. RWD Driveshafts • Requirements • Must be flexible • Must be able to change its length • Must be balanced • Must be properly phased • Very important on two-piece driveshafts

3. RWD Driveshafts • Construction • Materials • Mild steel • Aluminum • Carbon fiber Caution: Never clamp a driveshaft in a vise by the tube!

4. RWD Driveshafts • Design • The longer the driveshaft, the larger the diameter must be • The higher the operational RPM of the driveshaft the larger the diameter must be • Critical speed: rotational speed at which a driveshaft will begin to bow or break • Slip joint – two styles • Slip yoke – slides on transmission output shaft • Integral slip joint – stationary yoke at both ends with a slip joint in the middle • Damper – may be used to cancel vibrations and harmonics

5. Universal Joints • Two types • Single Cardon – cross and yoke • Double Cardon – constant velocity u-joint

7. Universal Joint • Construction • Cross • Seal • Cap • Retaining clips • Needle bearings • Zerk fitting

8. Universal Joints • Three methods of retaining the caps • External clips (Dana) • Internal clips (Cleveland) • Plastic molded • From the factory • Heat to remove • Replace with internal or external clips

9. Balance • Driveshaft MUST be balanced • Weights spot welded to tube • If sudden u-joint failure occurs or a sudden vibration develops check driveshaft balance • If driveshaft vibrates after installation remove and reinstall 180 degrees • Out of balance driveshaft will vibrate at medium to high speeds • May cause pinion bearing, transmission bushing, or seal damage

10. U-joint Angle • Place vehicle on level ground • No load on vehicle • Measure with an inclinometer • Transmission output shaft angle • Driveshaft tube angle • Pinion angle • Difference between output shaft and driveshaft tube is the front joint operating angle • Difference between pinion angle and driveshaft tube is rear joint operating angle

11. U-joint Angle

12. U-joint Angle • U joint operating angle should be between 1 and 3 degrees • Minimum operating angle of .5 degrees • Front and rear angle should be equal and opposite • This allows normal speed and torque fluctuations in the u-joint to be cancelled out • Non-equal or opposite operating angles will set up damaging vibrations • Non equal angles are due to non-OEM modifications

14. Two piece Drivelines • Two piece driveshafts are used when operational length is longer than a one piece driveshaft can reliably handle

15. Two-piece Driveshafts • Must be properly phased • Mark before disassembly

16. FWD Drivetrain • Constant velocity type joints are used • Components • Inner joint • Half-shaft • Outer joint • Boots • Splines

17. Inner Joint • Tulip style • Allows the shaft to change length • May be called tripod, or tipode style

18. Outer Joint • Allows for turning angles • Three types • Rzeppa • Non-pluging outer joint • Allows sharp turning angles (up to 48 degrees) • Outer housing often integral with the stub axle (splines) • Double offset joint • Looks like an Rzeppa but outer joint has straight grooves to allow plunging • May be used as an inner joint • Cross groove joint • Like an Rzeppa but grooves in inner and outer joints are cut at an angle • Plunges up to 1.75” • Used on many German and some domestic cars

19. Joint Types

20. RWD Driveline Diagnosis • U-joints • Check for looseness • If rust is present around seals suspect lack of lube • May show up as a vibration –binding joint • Slip joint • Check for looseness • Tube • Check for dents, runout (max .020” normal .005”), and missing weights

21. FWD Driveline Diagnosis • Always check boots when doing any under car service • Outer Joint • Clicking while turning under power • Shudder or vibration at highway speeds • Inner joint Clunk or vibration during acceleration or deceleration