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