Chapters 7-11
Use of ball bearings
Used at the rear wheels of a rear wheel drive vehicle with a solid rear axle
Simple universal joint components
2 Y shaped yokes, spider, trunnions
Steel drive shaft length
65 inches
CV joint boot failure
A CV joint can fail within eight hours of driving time due to dirt moisture and lack of lubrication if the boot is torn
Bearing dimensions
Bearing bore or inside diameter, bearing series or usage, and external dimensions
Carbon fiber plastic driveshafts
Can be made in extended lengths without the need for a center support bearing
Limited slip differential
Can send more toward to the wheel with traction than the wheel with poor traction. Can deliver as much as five times the torque to the tire with good traction which would be a TBR of 5:1. Are known as torque biasing devices or TBD
Locked differential
Canex both axle shafts together to eliminate the differential action but rarely used in original equipment applications except for vehicles that are designed for off-road travel and then only at low speed
Torque steer
Caused by unequal length drive axle shafts and causes steering wheel to pull during acceleration
Purpose and function of the drive axle assembly
Changing direction and multiplying engine torque, allowing the wheesl to rotate a different screens, support the weight of the vehicle, drive the wheels through the axles
Backlash
Clearance at the coast side of the tooth
Constant velocity joint
Constant velocity joints or designed to rotate with out changing speeds
Rzeppa maximum angle
40°
Gear heel
Outer ends of the ring gear teeth
Shifter placement
Internal or remote
Symptoms of defective wheel bearings
A hum rumbling or growling noise that increases with vehicle speed, roughness felt in the steering wheel that changes with speed or cornering, looseness or play in the steering wheel, grinding noise indicating a defective front wheel bearing, pulling during braking
Torque bias ratio
A ratio of the torque applied to each wheel
Tripod fixed joint
A type of CV joint used on some Japanese vehicles. Must be replaced with an entire axle shaft assembly
Driveshaft construction
A typical driveshaft is a hollow steel tube. Some driveshafts can be made of aluminum or carbon fiber plastic
Driveshaft balance
All driveshafts rotating at greater than 1000 RPM must be balanced within .5% of the driveshaft weight
Tripod plunge joint
Also called tripot, tripode, or tulip design
Axle shaft weight
Although it may look like a balance weight, it is actually a dampener weight used to dampen out certain driveline vibrations. Follow manufacturers instructions regarding either transferring or not transferring the weight a new shaft
Torque equalizer
Another name for a differential. It splits the engine torque equally to the drive wheels
LOBRÖ joint
Another name for constant velocity joints. The brand name of an original equipment manufacturer
Grease additives
Antioxidants, antiwear agents, rust inhibitor's, extreme pressure additives such as sulfurized fatty oil or chlorine
Electronic torque management
Basically front wheel drive vehicles that have a rear drive axle with no differential with the ring gear mounted on a spool to drive to clutches
Incorrect joint working angles
Defective or collapsed engine or transmission mounts, defective or sagging Springs, accident damage or aftermarket chassis, vehicle modification that raises or lowers the ride height
Pitch line
Design center of contact between the two gears approximately halfway up the tooth
Self applying clutch differential
Do not maintain a constant preload on the clutch packs. Use a four pin differential with two separate differential pinion shaft. Two shafts are called mate shafts.
Road test vehicle
Drive with light to moderate Frado acceleration, cruise with enough throttle to maintain a constant speed, float just enough throttle to keep engine load off the drivetrain, coast, Coast while in neutral
Live versus dead axle
Driven versus nondriven axle
Sealed front-wheel-drive bearings
Either two preloaded tapered roller bearings or a double row ball bearing. Usually called hub assemblies. Most often double row ball bearings because of reduced friction and greater seize resistance
Electric locking differential
Eliminates any differential action by coupling two of the differential parts together. Use an electric motor or magnetic clutch assembly to move the locking mechanism
Gear toe
Enter end of the ring gear teeth
Components of torque tubr
Front input shaft and flex coupling, driveline support tube, driveshaft, rear flex joint, rear yoke and bearing assembly
Nonhunting gear sets
Gear sets with final drive ratios expressible as a whole number. Required timing marks. As the pinion gear drives the ring gear each pinion tooth contacts only a few ring your teeth during each revolution
Partially nonhunting gearsets
Gearsets with final drive ratios expressible as a reducible fraction not equaling a whole number. Require timing marks. Each pinion tooth contacts only some of the ring pinion teeth.
Hypoid gearset
Has the pinion gear below the centerline of the ring gear. Allows a lower driveshaft so that the tunnel in the floor of the vehicle can be smaller. Allows a larger and stronger drive pinion gear in which the gear teeth slide across the teeth of the ring gear. Makes the gears quieter. Requires special GL four or GL five lubricant
Independent rear suspension drive axles
Have wheels that are supported by the suspension system and the driveshafts. The axle housing is very short, and short output shafts are used to connect the actual gears to the U joint halfshaft flanges
Quick backlash test
Hold one wheel still. Try to turn the other wheel. It should not move more than 1 inch
Hole in the retainer plate
If the axle does not have a hole in the retainer plate in the axle uses a c-lock type retaining method
Tapered roller bearing
Is the most commonly used automotive wheel bearing. The bearing and rollers are both tapered. This type of bearing it can withstand radial loads as well as axial loads in one direction
Drive side of the ring gear
Is the vertical convex side of the tooth. This is the side of the tooth that contacts the pinion gear while the engine is driving the vehicle forward
Needle bearing
Is a type of roller bearing that uses smaller rollers called needle rollers. The clearance between the diameter of the straight roller is manufactured into the bearing to provide the proper radial clearance and is not adjustable
Driveshaft noise
It is common to line the inside of the hollow drive shaft with cardboard or rubber
Universal joint angle
Joint working angles should be between 1/2 to 3°. joint angles should not differ by more than one half a degree between the front and rear joint or vibrations maybe felt
Cardan joints
Joints that are cross yoke. Named after 16th century Italian mathematician who worked with objects moving freely in any direction
Aluminum driveshaft
Lighter than steel. Can be as long as 90 inches. Used in extended cab pick up trucks to eliminate the need for a center support bearing
greasing u-joints
May require a special alemite tool
Ring gear runout
Measure if there is evidence of damage to the reindeer caused by a faulty or bent differential case or an improper mounting of the ring gear
Bearing failure analysis
Metal fatigue, electrical arcing, shock loading
Amount of lubrication
More Rolling bearings are destroyed by over lubrication then bye under lubrication because the heat generated in the bearings cannot be transferred easily to the air through the excessive grease
CV joint failure
Most common symptom is noise while driving. And outer CV joint will most likely be heard when turning sharply and accelerating simultaneously. This noise is usually a clicking sound. Inner joint failure is less common and often creates a loud clunk while accelerating from rest
Removable carriers
Most early trucks and cars had removable carriers which could be unbolted and removed from the housing for service. They are known as third member, drop out, or pumpkin
Integral carriers
Most rear wheel drive passenger vehicles and lite trucks use integral carriers and the axle tubes are welded to extensions of the carrier. And integral carrier is stronger in the areas around the carrier bearings. Some called a Salisbury or Spicer axle have removable rear cover for access to differential and other internal parts
CV joint boot composition
Natural rubber, silicone rubber, hard thermoplastic, urethane
Relieving the joint
New u joints are slightly stiff after being installed. Tap joint with a brass punch and a light hammer
Preloaded clutch differential
Offers two paths of work flow. One path is through the differential gears and the other is directly through the clutch packs. Has the tendency to lock up under high torque conditions due to gear separation force
Grease definition
Oil with a thickening agent to allow it to be installed in places where a liquid lubricant would not stay. Named for their thickening agent such as aluminum, barium, calcium, lithium, or sodium
Three types of differentials
Open differential, limited slip differential, locked differential
Bearing cap retainers
Outside snap ring, inside retaining ring, injected synthetic
Overhung pinion
Pinion gear hangs over from the rear bearing of the two tapered roller bearings. Most common style. Two tapered roller bearings are positioned as far apart as practical to hold the shaft rigid and not allow any movement of the pinion gear
Differential gears
Pinion or spider gears and splined axle or side gears. All floating. Spur bevel gears
Measuring joint working angles
Place an inclinometer on the U joint bearing cap. Observe reading. Rotate the driveshaft 90° and read angle. Subtract angle measures
Rear u joint working angle correction
Place metal shims between the rear leafspring and axle pedestal. Use caution to avoid loss of lubrication at the Pinion bearing
Wheel speed sensor placement
Placement at the axle housing can be affected by metal particles since they contain a magnetic core. Sensors at the axle shafts can be affected by worn axle bearings
Types of limited slip differentials
Preloaded clutches, self applying clutches, viscous couplings, eaton locker differential, hydraulic applied clutches, cone type, electronic locking differential
Torsen differential
Pure mechanical worm gear differential
Differential
Responsible for allowing the drive wheels to rotate at different speeds when turning or when the vehicle is traveling over uneven road surface. The differential carrier is the heavy cast portion of the rear axle assembly that provides mounting points or the draft pinion shaft bearings and carrier bearings
Two types of semi floating axles
Retainer plate type (ball bearing) and c-lock type (roller bearing)
Type of axle retaining method
Retainer plate type and c-lock
Final drive reduction gears
Ring and pinion gears
Hypoid gearset manufacturing
Ring and pinion gears are made as a matched set. Are typically made using either a two cut or five cut method
Major components of drive axle
Ring and pinion gears, differential assembly, axle shafts
Four types of rolling contact bearings
Roller, ball, needle, tapered roller
Carrier or side bearings
Securely mount ring and pinion gears. Preevent gears from separating under torque load
Service versus factory shims
Service shams are made from steel and can be driven into place where as factory shams are made of cast iron and should be discarded when disassembling the axle
Hunting gearsets
Sets with final drive ratios expressible and a fraction that cannot be reduced to any lower terms. Requires no timing marks or alignment during assembly. As the pinion gear drives the ring gear each pinion tooth will hunt for or seek contact with every ring gear tooth
Maximum angle for Cardan joints
Single joint 12°. Double joint 18 to 22°
Positraction
Specific name of the limited slip differential used in Chevrolet vehicles. The RPO code is G80
Static versus dynamic seals
Static seals are used between two surfaces that do not move. Dynamic seals are used between two surfaces that move. Wheel bearing seals are dynamic type seals that must seal between rotating axle hubs and stationary spindles or axle housing. Most use a synthetic rubber lip seal encased in metal. The lip is often held in contact with the moving part with the aid of a garter spring
Limited slip differential problems
Sticking or slipping condition in which the plate stick together, break apart, and stick together instead of sliding smoothly over each other. Heard as a series of cloth as the vehicle rounds a corner. It is important to keep the drive tires the same diameter.
Retaining method for u-joint
Strap type and u-bolt type
semi floating axles
Used in all rear wheel drive passenger vehicles. Enter and floats because it is supported by a deer not a bearing. Outer and uses a bearing in the end of the housing. This bearing transference the load of the vehicle to the axle which in turn transfers it to wheel
Constant velocity joint first use
The first CV joint was used on the 1929 cord built in Auburn Indiana
Rzeppa joints
The first cost of velocity joint was designed by Alfred H Rzeppa in the mid-1920s. It transfers torque through six round balls that are held in position midway between the two shafts. This design causes the angle between the chance to be equally split regardless of the angle
Universal joint series number
The higher the series number the larger and higher torque rating the joint
Inner versus outer wheel bearing
The inner wheel bearing is always larger because it is designed to carry most of the vehicle weight and transmit the way to the suspension through the spindle
NLGI number
The national lubricating grease Institute uses the penetration test as a guide to assign grease a number. Low numbers are fluid and higher numbers are more firm. Number two grease is the most commonly used. GC and LB is highest quality
Axle ratio
The number of revolutions of the driveshaft that are required to turn the wheels one revolution
Tooth face
The part of the tooth above the pitch line
Tooth flank
The part of the tooth below the pitch line
Straddle mounting
The pinion gear is straddled by two bearings where the rear tapered bearing is located in front of the gear and a pilot bearing behind the gear. The pilot bearing is usually a small roller bearing. This is the strongest mounting. It also aluminates gear to bearing the leverage of facts and allows the bearings to be placed fairly close to each other
Coast side of the ring gear
The slanted concave side of the tooth. Receives pressure while the vehicle is coasting in the vehicle is driving the engine
Float
There is no load on the gear teeth and backlash will be on both sides
Axle shafts
Transferred torque from differential side gears to drive wheels and support the weight of the vehicle. Made of forged steel
Driveshaft purpose
Transmits engine torque from the transmission or transaxle to the axle assembly or drive wheels
Type of CV joint grease
Type of CV joint, location of the joint on the vehicle, the type of boot
Bearing overload
Typically in pick up trucks, the axle bearings my support of the entire weight of the vehicle including its cargo so if they bump is hit while driving the balls or the rollers can make an indent in the race of the bearing. This is called brinelling named after Johan a Brenel Who used hard balls to test surface hardness
U-joints purpose
Universal joints allow the wheels and the rear axle to move up and down, remain flexible, and still transferred torque to the drive wheels
Viscous coupling differential
Use a stack of intermeshed clutch plates that run in a bath of silicone fluid and are not spring loaded
C-lock type rear axles
Use a straight roller bearing supporting a semi floating axle shaft inside the axle housing
Retainer plate type rear axles
Use four fasteners that retain the rear axle in the axle housing
Ball bearings
Use hardened steel balls between the inner and outer race to reduce friction. Ball bearings cannot support the same weight as roller bearings, but there is less friction in ball bearings and they generally operate at higher speeds
Roller bearing
Use rollers between an inner and outer race to reduce friction. A roller bearing having a longer contact area can support heavier loads in a ball bearing
Anti-friction bearings
Use rolling parts inside the bearing to reduce friction
Three-quarter floating axles
Used an older vehicles. Used a single roller or ball bearing between the hub and axle housing. Vertical loads pass from the hub through this bearing to the housing but cornering loads which try to pull the axle out of the housing act on the axle
Eaton locker differential
Used in some pick ups and includes a governor, latching mechanism, and differential cam gear. Good for wheel speed difference of up to 100 RPM
Full floating axle
Used on all heavy trucks. The wheel hub has a pair of large tapered roller bearings that transfer all of the vehicle loads except torque from the axle housing it to the wheel. The axle shaft slides into mash with the axle gear and is bolted to the hug. Even if the axle shaft is removed the vehicle will still roll down the road
Cross groove plunge joint
Used on many German front wheel drive vehicles. Parts are tripod, cross groove, double offset
Torque tube driveline
Used on some vehicles like the Corvette or Cadillac XLR with rear mounted transmissions and virtually eliminates the effects of rear end torque on the rear axle
Cone clutch design
Uses a pair of cone clutches in place of the clutch plates
Electronic traction control
Uses wheel speed sensor, control module, and hydraulic modulator of the antilock brake system to sense wheel spin and apply the brakes on that wheel. This will transfer torque to the other drive wheel
Velocity with universal joints
Velocity changes twice per revolution and depends upon the angle of the joint
Drive axle service
Verify customer complaint, identify the vehicle and drive axle including gear ratio, visual identification number, RPO code, research investigate vehicle history, vehicle build, check vehicle history, safely raise vehicle and do visual check, disassemble and inspect all internal components, test backlash and operation of limited slip, replace all components that do not meet factory specifications, verified repair
Three symptoms of defective U joints
Vibration or harshness at highway speed, a clicking sound whenever the vehicle is moving either forward or in reverse, a clunking sound when changing gears. A clicking sound while moving in reverse is usually an indication of the needle bearings being forced to rotate in the opposite direction in a defective U joint
Reverse cut ring and pinion gears
Were primarily designed for front wheel drive applications to take advantage of their increased strength
Spline bind
Where the change in rear pinion angle causes the driveshaft slip splines to move as the shaft length changes. Clunking noise
CV joint grease
molybdenum-disulfide grease (moly grease)
Center support bearing
must be used if the driveshaft surpasses the critical length based on the material. Also called a steady bearing or hanger bearing
