Deck 22: Driveshaft Assemblies

Question 1

Which of the following terms is another way of describing a U-joint cross?

A) spider
B) hanger
C) yoke
D) spline

Answer 1

A

Question 2

Which of the following types of universal joint damage would most likely result from improper installation?

A) galling
B) spalling
C) pitting
D) brinelling

Answer 2

D

Question 3

Which of the following is a function of the slip yoke used on a driveshaft?

A) slips to dampen clutch engagement and road shock
B) allows the driveshaft to change length as differential carrier operating angle changes
C) permits the transmission slide back for service
D) all of the above

Answer 3

B

Question 4

Which of the following components consists of a hardened,splined stubb,welded to the end of a driveshaft tube,and mates to a yoke with matching internal splines?

A) universal joint
B) slip yoke
C) hanger bearing
D) cardan joint

Question 5

Which of the following operating conditions requires the most frequent lubrication of the driveshaft?

A) 4x4 vocational off-highway
B) pick-up and delivery
C) linehaul trucking
D) less-than-load

Question 6

Which of the following describes a broken back driveline arrangement?

A) working angles of its U-joints are equal
B) companion flanges or yokes are not parallel
C) both A and B
D) neither A nor B

Question 7

When a universal joint assembly is equipped with a standpipe,what is the function of the standpipe?

A) improves access to the zerk fittings
B) aligns the trunnions during assembly
C) prevents reverse flow of hot lubricant during operation
D) all of the above

Question 8

What factors determine the required driveshaft diameter and wall thickness?

A) maximum torque load
B) gross vehicle weight
C) type of operation
D) all of the above

Question 9

A technician greasing a driveshaft slip spline assembly applies lubricant until it appears at the pressure relief hole.What should be done next?

A) cover the relief hole with a finger and add some more lubricant
B) cease applying lube to avoid over-greasing
C) continue applying lube until it appears at the slip yoke seal
D) both A and C

Question 10

How often should a typical driveshaft hanger bearing be lubricated?

A) when U-joints are lubed
B) they are usually factory lubricated and are not serviceable
C) each time the slip yoke is lubed
D) both A and C

Question 11

Which of the following are recommended lubricants for heavy-duty truck U-joints?

A) lithium-based grease with EP additives
B) NLGI grade 1 or 2 grease
C) NLGI grade 3 or 4 grease
D) both A and B

Question 12

Which of the following would represent ideal operating conditions for a pair of universal joints on a propeller shaft?

A) maximum operating angle of 3 degrees
B) minimum operating angle of 1/2 degree
C) operating angles each U-joint should be within 1 degree
D) all of the above

Question 13

Why should a driveshaft maintain flexibility while continuously transferring torque between powertrain components?

A) drivetrain components change angles in relation to each other during operation
B) must continuously change length as drive axles react to torque and road changes
C) driveshafts expand and contract with temperature changes
D) all of the above

Question 14

When are the two universal joints on a driveshaft operating in-phase?

A) transmission and rear axle are on the same horizontal plane
B) the two shaft sections are on the same vertical plane
C) the slip-yoke lugs and the tube-yoke lugs are aligned with each other
D) all of the above

Question 15

When a one-piece,parallel-joint driveline arrangement with 2 universal joints is used,which of its angles must be equal and opposite?

A) working angles of its two U- joints
B) angles of both mating yokes
C) angle of the transmission output shaft and the axle pinion shaft
D) all of the above

Question 16

All of the following conditions can cause driveshaft vibration EXCEPT:

A) driveshaft out-of-balance
B) insufficient difference in U-joint operating angles
C) improper phasing
D) unequal U-joint working angles

Question 17

When lubricating universal joints,which of the following is best practice?

A) apply grease until you hear the first trunnion seal pop
B) pump grease until it exits from all four trunnion seals
C) apply two shots of grease per trunnion
D) disassemble and hand pack each bearing cap

Question 18

What is usually considered to be the maximum recommended length for a single-piece driveshaft operating at speeds of 3,000 rpm?

A) 50 inches (127 centimeters)
B) 70 inches (178 centimeters)
C) 90 inches (228 centimeters)
D) 95 inches (240 centimeters)

Question 19

When greasing a driveshaft U-joint,grease exits from three trunnion seals but not the fourth.What should be done next?

A) heat the trunnion with a rosebud
B) loosen the bearing cap on the affected trunnion and try again
C) remove the U-joint and hand pack each bearing cap
D) replace the U-joint

Question 20

Which of the following components contains a forged journal cross and trunnions?

A) slip yoke
B) center support
C) universal joint
D) hanger bearing

Question 21

When chips and flakes of metal separate from a U-joint trunnion race due to metal fatigue,how would the failure be categorized?

A) brinelling
B) false brinelling
C) spalling
D) galling

Question 22

What equipment is required to test and balance a driveshaft when it is on chassis?

A) electronic inclinometer
B) strobe light and balance sensor
C) protractor and chalkline
D) good intuition

Question 23

When installing a U-joint into a heavy-duty truck driveshaft,where should the lube zerk be located?

A) 180 degrees offset from the zerk at the other end
B) 90 degrees offset from the zerk at the other end
C) aligned with the zerk at the other end
D) it does not matter

Question 24

When attempting to dynamically balance a truck driveline,which of the following must be done?

A) all the wheels must be off the ground
B) the frame must be level
C) the transmission and differential carrier must be at the same angle raised as on the ground
D) all of the above

Question 25

Which of the following methods can be used to adjust drive carrier operating angle when correcting driveline angles on a truck with a leaf spring rear suspension?

A) cold bend axle housing
B) install axle shim wedges
C) rotate axle stubbs
D) shim the U-joint

Question 26

Technician A says that to properly lubricate a driveshaft U-joint with twin zerks,grease must be pumped into both nipples.Technician B says that if grease exits all four trunnion seals on a U-joint,it indicates that it has been properly greased and purged.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 27

Technician A says that U-joint bearing caps and trunnions once in use should be regarded as a matched set and not interchangeable.Technician B says that when one U-joint fails on a driveshaft,its opposite one must also be changed.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 28

Which of the following is recommended to be applied to the exterior of a set of U-joint bearing caps before installation into the yokes?

A) never-seize compound
B) engine lube
C) chassis grease
D) silicone RTV compound

Question 29

Which of the following methods of separating a U-joint from a driveshaft yoke when it is on the truck,is preferred?

A) hydraulic jack on yoke hub
B) 50 lb (25 kg)slide hammer on yoke
C) 16 lb (7 kg)sledge hammer
D) two-jaw U-joint puller

Question 30

Technician A says that driveshaft U-joints are expensive and engineered to last the life of the vehicle.Technician B says that replacing driveline propeller shaft assemblies is a common shop practice.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 31

When checking the dynamic balance of a truck driveshaft,an initial spin up indicates the balance is out.Which of the following should be performed FIRST before proceeding?

A) remove any existing balance weights with a chisel
B) clamp one steel washer to the counterbalance position
C) remove the propeller shaft assembly
D) replace both the U-joints

Question 32

What is used on a driveline hanger bearing to buffer driveshaft vibrations and road shock?

A) coaxial springs
B) rubber insulators
C) gusset braces
D) vertical springs

Question 33

When performing dynamic balance of a truck driveshaft using counterweights and a hose clamp,where should the hoseclamp worm be positioned when testing?

A) 180 degrees offset from counterweight
B) 90 degrees offset from counterweight
C) over the counterweight
D) it does not matter

Question 34

If a driveshaft is assembled out-of-phase which of the following must have occured?

A) U-joint assembled backward
B) transmission yoke has been changed
C) differential carrier yoke has been changed
D) driveshaft has been separated at the slip splines

Question 35

Technician A says that as driveshafts speeds increase,permissable U-joint working angles also increase.Technician B says that when a truck diesel engine is run at a rated speed and the transmission is in overdrive,driveshaft speeds can exceed 3000 rpm.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 36

A driveshaft U-joint has failed.Technician A says that the complete driveshaft assembly should be removed from the chassis to replace the U-joint.Technician B says that the driveshaft must be separated at the slip spline to make the repair.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 37

What is usually regarded as the absolute maximum length a driveshaft should be without adding a center support bearing?

A) 70-inches (178 cm)
B) 75-inches (190 cm)
C) 80-inches (203 cm)
D) 90-inches (228 cm)

Question 38

Technician A says that a driveshaft with U-joints speeds up and slows down once per rotation.Technician B says that to avoid torsional vibrations,the rear U-joint needs to cancel out the non-uniform rotation of the forward U-joint.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 39

What is the recommended tool used to measure the operating angles of driveline components?

A) protractor
B) electronic inclinometer
C) balance sensor and strobe
D) carpenter's level

Question 40

What is the function of the hanger bearing shim pack used between the bearing mount and the chassis crossmember?

A) dampens chassis vibrations
B) dampens road shock
C) sets driveshaft angles
D) both A and B

Question 41

Technician A says that a PTO driveshaft should be made of a solid steel bar when the auxiliary it drives has to be driven at a speed greater than 1200 rpm.Technician B says that solid PTO driveshafts can be made from round section,square section,and hex section steel stock.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 42

Which of the following would indicate that a driveshaft was likely ovalled when measuring it with a dial indicator?

A) needle deflects twice in one revolution
B) needle deflects only on the negative side of the scale
C) needle deflects only on the positive side of the scale
D) needle travel greater than 0.010 inch (0.25 mm)

Question 43

Which of the following driveshaft tube ratings would be most common in linehaul highway tractors?

A) 1500 series
B) 1600 series
C) 1700 series
D) 1800 series

Question 44

Technician A says that a driveshaft with U-joints speeds up and slows down twice per full rotation.Technician B says that minimize torsional vibrations,U-joint working angles should be set as high as possible.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 45

Technician A says that because PTO driveshafts are commonly driven at speeds lower than 1200 rpm,solid steel stock shafts can be used.Technician B says that because PTO driveshafts are used intermittently and at lower speeds,precision balancing is not usually required.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 46

What instrument should be used to measure driveshaft runout?

A) inclinometer
B) dial indicator
C) outside micrometer
D) bore gauge

Question 47

When a 1/4 inch (6 mm)shim is added to a rear carrier torque arm,by how much will the rear carrier U-joint operating angle be altered?

A) 1/4 degree
B) 1/2 degree
C) 3/4 degree
D) 1 degree

Question 48

When measuring the total indicated runout (TIR)of a driveshaft,you record 0.003" (0.08 mm)positive and 0.005" (0.13 mm)negative through one shaft revolution.What is the TIR?

A) 0.015 inch (0.05 mm)
B) minus 0.002 inch (minus 0.05 mm)
C) 0.008 inch (0.21 mm)
D) 0.002 inch (0.05 mm)

Question 49

Technician A says that the maximum permissable operating angles of U-joints decrease as driveshaft rpm increases.Technician B says that a driveshaft that turns at a maximum of 3500 rpm should have U-joint working angles of 3 degrees or less.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 50

If you add shims to a longitudinal torque rod attached to the forward drive axle carrier in a tandem drive truck,which of the following will result?

A) only the working angles of the U-joints in the front driveshaft will change
B) only the working angles of the U-joints in the rear driveshaft will change
C) the working angles of the U-joints in both driveshafts will change
D) no U-joint working angles will be affected