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Slide 2 68 Drive Shaft and Transfer Case Technology Chapter Slide 3 Permission granted to reproduce for educational use only. Goodheart-Willcox Co., Inc. Objectives After studying this chapter, you will be able to: Identify and describe the parts of a modern drive shaft assembly. Explain the functions of a drive shaft. Describe the different types of universal joints. List the different types of drivelines. Explain the basic operation of a transfer case. Correctly answer ASE certification test questions that require a knowledge of drive shafts and transfer cases. Slide 4 Permission granted to reproduce for educational use only. Goodheart-Willcox Co., Inc. Drive Shaft Assembly Drive shaft assembly components Slip yoke Connects transmission output shaft to front universal joint Drive shaft Hollow metal tube that transfers turning power from front universal joint to rear universal joint Slide 5 Permission granted to reproduce for educational use only. Goodheart-Willcox Co., Inc. Drive Shaft Assembly (Cont.) Rear universal joint Flex joint connecting drive shaft to rear yoke Rear yoke Holds rear universal joint and transfers torque to gears in rear axle assembly and differential Slide 6 Permission granted to reproduce for educational use only. Goodheart-Willcox Co., Inc. Drive Shaft Assembly (Cont.) (Mazda) Slide 7 Permission granted to reproduce for educational use only. Goodheart-Willcox Co., Inc. Functions of Drive Shaft Assembly Sends turning power from transmission to rear axle assembly Flexes and allows vertical movement of rear axle assembly Provides sliding action to adjust for changes in driveline length Provides smooth power transfer Slide 8 Permission granted to reproduce for educational use only. Goodheart-Willcox Co., Inc. Drive Shaft Operation Transmission output shaft turns slip yoke Slip yoke then turns front universal joint, drive shaft, rear universal joint, and rear yoke on differential Differential contains gears that transfer power to rear drive axles Axles rotate wheels Slide 9 Permission granted to reproduce for educational use only. Goodheart-Willcox Co., Inc. Driveline Flex When tires strike a bump in the road, rear suspension moves upward and springs are compressed Universal joints Let driveline flex as rear axle moves up and down Protects drive shaft from any damage caused by movement Slide 10 Permission granted to reproduce for educational use only. Goodheart-Willcox Co., Inc. Slip Yoke Slip yoke, or slip joint Splined to transmission output shaft Allows for changes in driveline length by sliding in and out of transmission (Ford) Slide 11 Permission granted to reproduce for educational use only. Goodheart-Willcox Co., Inc. Slip Yoke (Cont.) Extension housing bushing Supports slip yoke as it spins in transmission Transmission rear seal Rides on slip yoke and prevents fluid leakage from rear of transmission Slide 12 Permission granted to reproduce for educational use only. Goodheart-Willcox Co., Inc. Rear Yoke Rear yoke is yoke bolted to outer end of pinion gear on rear axle assembly It transfers torque to gears in rear axle assembly Rear universal joint held by this yoke Slide 13 Permission granted to reproduce for educational use only. Goodheart-Willcox Co., Inc. Drive Shaft Drive shaft or propeller shaft Hollow steel tube with permanent yokes welded on each end Very strong and light Spins much faster than wheels and tires It must be straight and perfectly balanced Slide 14 Permission granted to reproduce for educational use only. Goodheart-Willcox Co., Inc. Drive Shaft Assembly (Toyota) Slide 15 Permission granted to reproduce for educational use only. Goodheart-Willcox Co., Inc. Drive Shaft Balance Drive shaft must be perfectly balanced, with its weight evenly distributed around its centerline Drive shaft balancing weights Welded to shaft to reduce vibration Drive shaft vibration damper Large, ring shaped weight mounted on rubber Helps keep shaft spinning smoothly by absorbing torsional vibration Slide 16 Permission granted to reproduce for educational use only. Goodheart-Willcox Co., Inc. Universal Joints Universal joint or U-joint Swivel connection capable of transferring turning force between shafts at angle to one another Simple universal joint made of two Y-shaped yokes (knuckles) connected by cross (spider) Slide 17 Permission granted to reproduce for educational use only. Goodheart-Willcox Co., Inc. Cross-and-Roller Universal Joint Cross-and-roller joint or cardan universal joint Most common type of drive shaft universal joint Bearing caps are held stationary in drive shaft yokes Roller bearings fit between caps and cross to reduce friction Cross is free to rotate inside caps and yokes Slide 18 Permission granted to reproduce for educational use only. Goodheart-Willcox Co., Inc. Cross-and-Roller Universal Joint (Cont.) (Chrysler) Slide 19 Permission granted to reproduce for educational use only. Goodheart-Willcox Co., Inc. Constant Velocity Universal Joint Constant velocity universal joint or double-cardan joint Two cross-and-roller joints connected by centering socket and center yoke Two joints operate together on one end of drive shaft Output shaft speed fluctuations are counteracted Slide 20 Permission granted to reproduce for educational use only. Goodheart-Willcox Co., Inc. Constant Velocity Universal Joint (Cont.) (Ford) Slide 21 Permission granted to reproduce for educational use only. Goodheart-Willcox Co., Inc. Ball-and-Trunnion Universal Joint Ball-and-trunnion joint Another joint designed for constant velocity Eliminates shaft speed fluctuations Allows for slight length changes in driveline Ball-and-trunnion joint seldom used Slide 22 Permission granted to reproduce for educational use only. Goodheart-Willcox Co., Inc. Center Support Bearing Center support bearing Holds middle of two-piece drive shaft Center bearing bolts to vehicles frame or underbody Supports center of drive shaft where two shafts come together Slide 23 Permission granted to reproduce for educational use only. Goodheart-Willcox Co., Inc. Center Support Bearing (Cont.) (Fiat) Slide 24 Permission granted to reproduce for educational use only. Goodheart-Willcox Co., Inc. Driveline Types Hotchkiss driveline Exposed drive shaft that operates rear axle assembly mounted on springs Usually has cross-and-roller universal joints Torque tube driveline Solid steel drive shaft enclosed in large hollow tube With independent rear suspension, drive shaft can be one piece without universal joint Slide 25 Permission granted to reproduce for educational use only. Goodheart-Willcox Co., Inc. Hotchkiss Driveline (Ford) Slide 26 Permission granted to reproduce for educational use only. Goodheart-Willcox Co., Inc. Transfer Cases Transfer case Sends power to both front and rear axle assemblies in four-wheel-drive vehicle Mounts behind and is driven by transmission Two drive shafts normally run from transfer case, one to each drive axle Slide 27 Permission granted to reproduce for educational use only. Goodheart-Willcox Co., Inc. Transfer Cases (Cont.) (Ford) Slide 28 Permission granted to reproduce for educational use only. Goodheart-Willcox Co., Inc. Two-Wheel-Drive, High Range (2H) 2H range provided for normal driving when four- wheel-drive traction not needed Sliding clutch remains in neutral position Torque is not transferred to front axle assembly Slide 29 Permission granted to reproduce for educational use only. Goodheart-Willcox Co., Inc. Four-Wheel-Drive, High Range (4H) Sliding clutch is shifted into main shaft clutch gear Torque then flows through drive chain, front output yoke, and front drive axle assembly Both front and rear axles drive vehicle Slide 30 Permission granted to reproduce for educational use only. Goodheart-Willcox Co., Inc. Four-Wheel-Drive, Low Range (4L) Torque transfer is almost same as in 4H Ring gear is shifted forward into lock plate This holds ring gear stationary Planet gears walk inside ring gear, producing gear reduction Slide 31 Permission granted to reproduce for educational use only. Goodheart-Willcox Co., Inc. All-Wheel Drive All-wheel drive Four-wheel-drive system that does not use conventional transfer case Designed for front-wheel-drive transaxle or transmission Transmission or transaxle in all-wheel-drive system is modified to allow power flow to front and rear drive axles Slide 32 Permission granted to reproduce for educational use only. Goodheart-Willcox Co., Inc. Drive Systems