ASE A3 - Manual Drive Trains and Axles - Terms and Applications

What should you do if you measure too much backlash in a pinion gear?

Both the pinion gear and the ring gear need to be replaced

What are two reasons a manual transmission can jump out of gear during acceleration?

Broken shift linkage and worn motors mounts (which can stretch shift cables)

If a transfer case won't shift from a lower gear ratio to a direct drive or 1:1 ratio, what is the most likely cause?

Broken shift shaft

Describe the process of measuring driveshaft runout

Clean the center and 3" from each end with a wire brush. Place the dial indicator on the cleaned areas and rotate the driveshaft

Why would a growling sound be heard from the rear of a RWD vehicle?

Defective rear axle bearings

When disassembling a transmission for an overhaul, what should you keep in mind?

Every component should be inspected for damage while disassembling and index marks should be checked so that all parts are aligned properly

What are the symptoms of excessive clutch housing bore runout?

Excessive clutch housing bore runout can cause chatter, transmission jumping out of gear, grabbing, no release and premature pilot bearing/bushing wear.

What are two reasons an axle shaft on a rwd car could have excessive end play?

Faulty axle bearing or c-lock retainer

What gear could a 4 speed transmission jump out of if the input shaft has excessive end play?

Fourth gear

What can be done to a clutch when there is a squealing noise coming from it, even when it's not engaged?

If a clutch is squealing even when not engaged, this indicates permanent damage and the clutch should be replaced

How can you properly repair an extension housing with burrs and gouges on the mating surface?

If the burrs and gouges are not excessive, they can be repaired with a file

When removing an axle drive shaft in a vehicle with a transaxle, what is important to avoid?

If the vehicle is moved while the front drive shafts are out, the wheel bearings can become damaged

How should you torque down a pressure plate to a flywheel?

In a crisscross pattern

How do anaerobic sealers cure?

In the absence of air

What can happen if a ring gear on a flywheel is worn?

It can affect starter engagement

What are two ways to bleed a hydraulic clutch?

It can be bled by putting fluid into the slave cylinder screw or letting fluid out of the slave cylinder

What happens if a differential is overfilled?

It can cause axle seals to leak

What will happen if you forget to line up the yokes when replacing a u-joint on a drive shaft?

It can cause driveline vibration

What happens if axle bearings wear?

It can cause the axle seals to leak

What can happen when a manual transmission has a weak detent spring?

It can jump out of gear

Is the reverse idler gear splined or smooth?

It is free floating on the reverse idler shaft

If a noise is coming from all forward gears only, what could be the issue?

It is most likely an output shaft bearing but it could also be an input shaft bearing

As a clutch disk wears, what will happen to the free travel?

It will decrease

A remote vent on a differential on a 4WD vehicle is used to:

Keep moisture out of the differential

Should 4wd have a jerking feeling in the steering wheel when turning sharp in corners?

Many four-wheel drive vehicles use Cardan U-joints in the front outer axles; when turning sharply, they cause a jerking feeling in the steering wheel due to the angle. CV joints can be turned as sharp as 40 degrees without the jerking feel that Cardan U-joints cause

What should you do before removing a drive shaft?

Mark it before removal to ensure proper phasing upon reinstallation

The shift lever adjustment on a transmission with external linkage is usually performed with the transmission in which gear?

Neutral

What would be the MOST likely customer complaint for a damaged transmission case, center adapter plate or rear extension housing mating surface?

Oil leak

When installing a new universal joint, what should you keep in mind before preparing to grease them?

Pay close attention to the location of the zerk fitting—if installed incorrectly, then the zerks cannot be reached with a grease gun

What are three critical clutch pedal adjustments?

Pedal height, free play, and reserve

What are some facts about differential case/carrier and ring-gear removal and replacement?

Removal: The ring-gear runout and case/carrier side-play should be measured and the side bearing caps should be marked in relation to the housing before removal of the case/carrier and ring-gear assembly Installation: The side bearing should be clean and lubricated before installation

If a transmission is oil soaked, what should you inspect?

Rubber deterioration and swelling

How should you go about doing maintenance on a carrier support bearing?

Some of them have zerk fittings and require greasing

How is idler gear end play controlled?

With thrust washers

What is the proper way to check a limited slip differential?

You can use a torque wrench with the wheel off the ground to measure the amount of ft./lbs. it takes to rotate the wheel

What should you do if pinion depth on a ring gear is too deep?

The backlash (play between gears) needs to be increased to move the ring gear away from the pinion

If a transfer case is making a popping sound in 4wd only when accelerating from a stop, what could be the cause?

The chain is loose

What is the purpose of a chalk mark on a drive shaft?

The chalk mark is used to reference the heavy spot when balancing the driveshaft

What is a reason a vehicle would experience hard shifting into first gear?

The clutch could be out of adjustment

In a torque management transfer case of an A4WD car, what does it do when the two axles start moving at different speeds?

The computer will increase the clutch pack coil duty cycle on the front drive shaft to control spinning

What should you do if you find a chipped tooth on a countershaft?

The countershaft AND the mating gear should both be replaced

If a vehicle has a vibration that occurs in the rear over 30mph, what is one important step you can take to possibly cure the issue?

The flanges should be disconnected and rotated 180 degrees and runout should be checked again

What is the front axle position while in neutral on a FWD and 4WD pickup?

The front axles are disconnected while in neutral

When servicing a 4wd vehicle with tapered wheel bearings, what is one rule to remember?

The front wheel bearings should adjusted with 0.001-0.005 inches of end-play

If a manual transmission vehicle makes a loud growling noise that increases with engine speed when the clutch pedal is out and clutch is fully engaged, what is the issue?

The input shaft bearing is worn

In a vehicle with a 4 speed transmission, there is a growling noise in all gears except 4th. What are two possible reasons for the noise?

The input shaft bearing or the countershaft bearing

What should you do when disassembling a transaxle for overhaul?

The input shaft should be rotated and the transaxle shifted through the gears including reverse gear

What is the maximum allowable clutch housing bore runout?

The maximum allowable clutch housing bore runout is 0.010 inches

What is the difference when replacing a conventional wheel bearing and a unitized wheel bearing?

The race should be replaced on a conventional wheel bearing, while the race on a unitized wheel bearing does not need to be replaced.

In order to measure differential carrier runout, what has to be removed?

The ring gear

What could be a cause of repeat pinon seal failure?

The sealing surface of seal could have wear grooves, causing even new seals to leak

Where are the fiber plates splined to in an LSD?

The side gear

If a transaxle has brass flakes in its oil during an oil change, what has worn?

The synchronizers are wearing

What two things can happen if too much material is machined away during flywheel resurfacing?

The torsion springs on the clutch disk can contact the flywheel bolts and the slave cylinder rod may not have enough travel, causing the clutch to not release properly

What happens if the second-speed gear clutch teeth and blocking ring teeth are badly worn on a transaxle?

The transaxle can jump out of gear.

What can happen if shift linkage is misadjusted?

The vehicle can jump out of gear

Why would a 4wd indicator light flash while failing to shift into gear?

This can be caused by any electrical issue, such as a faulty shift motor

What are two ways to adjust slide bearing pre-load on a RWD differential?

Threaded adjusters and shims (determined by thickness of a single shim)

Describe the locations of the toe, heel, flank, and face on a ring gear tooth

Toe - inner end, Heel - outer end, Flank - bottom, Face - top

What is one type of tapered wheel bearing used in modern 4wd vehicles?

Unitized wheel bearings

What is the proper way to test a vehicle speed sensor signal?

Use an oscilloscope while the vehicle is being driven

How do you measure synchronizer block ring wear?

Using a feeler gauge

What are three ways to remove a differential from a housing?

Using a puller, a pry bar and wood, or using a box end wrench on one of the ring gear bolts and rotating the pinion

What could cause repeated viscous clutch failure in an AWD vehicle?

Using different sized tires

How do you adjust side bearing preload on a transaxle?

Using shims only

What can cause a limited slip differential to chatter?

Using the wrong type of fluid

What are two possible reasons a vacuum powered 4wd system would fail to shift?

A cracked vacuum line or faulty vacuum motor at the front axle could be the cause

What can be measured on a pinion gear?

A dial indicator stylus can be used to measure pinion gear runout

What are two causes of a broken speedometer?

A faulty vehicle speed sensor or speedometer drive gear could be the cause

What is a step used when setting pinion bearing preload that utilizes a hydraulic press?

A hydraulic press is used to simulate the load of the yoke when adjusting preload

If a front wheel drive has a growling sound that increases when turning right, what could be the cause?

A left driver side wheel bearing is worn

What is the proper way to install clutch pack disks on an limited slip differential (LSD)?

A limited-slip differential that uses a clutch pack should have the fiber discs soaked in differential lube, then installed alternately (steel, fiber, steel)

What can be done to fix a mainshaft with runout above specification?

A mainshaft out of specification should always be replaced. There is no proper repair procedure except replacement.

Why could a transaxle have repeated drive axle seal leakage and replacement?

A plugged transaxle vent

What type of hammer should you use to install rear main oil seals?

A seal driver, which is more delicate than other types of abrasive hammers

When a transaxle on a 4wd vehicle has fluid leaking from the output shaft seal, what could be the cause if the seal was checked and is still good?

A seal leak can be caused due to many reasons, including a bad seal, a damaged yoke surface, or even a plugged vent, causing excessive pressures.

What is the best tool to use to measure warping on mating surfaces on a transaxle?

A straight edge

If a front wheel drive vehicle makes a clunking noise on acceleration and deceleration, what is the issue?

A vibration or shudder indicates an inboard CV joint

What is a common symptom of an unbalanced drive shaft?

A vibration that increases with speed

If a manual transmission grinds when trying to go into first or reverse gear only, what could be the cause?

A warped clutch disk can cause a clutch spin-up problem that can cause transmission grind

What would cause a chirping sound from the bellhousing on a manual transmission?

A worn clutch release bearing

What is one reason a squeaking noise would occur in a driveshaft in reverse?

A worn cross shaft bearing surface

What types of oil are used to lubricate transfer cases?

ATF and gear oil

What is one reason a hydraulic clutch would fail to disengage fully, even when the pedal is fully depressed?

Air could be trapped in the clutch hydraulic system

What important step should be taken when removing a transfer case?

All yokes and flanges should be marked for correct reassembly

What should you do when adjusting the pinion depth on a ring gear?

Always replace the collapsible spacer

What are the differences in symptoms from an over tightened pinion nut and under tightened pinion nut?

An under tightened pinion nut will cause a clunking noise while an over tightened nut will cause growling in the bearings

What measurement should be checked when installing a bronze bushing style pilot bearing?

Any time the pilot bearing is replaced, it is a good idea to check the pilot bearing bore runout

What can cause the bushings on a transmissions extensions housing to wear on one side only?

Binding universal joints

What are two things to know about drive chains when they break in transfer cases?

1. If a drive chain breaks, you will still automatically have power to the rear wheels 2. Low range can still engage if the chain is broken

What are two reasons a limited slip differential (LSD) could be chattering during a turn?

1. Incorrect fluid could be used 2. The limited-slip differential additive wasn't used

What are two important rules to know about joint working driveline angles?

1. Most joint working angles should be at least 1/2 of a degree and should not exceed 3 degrees 2. Two joint working angles on a common shaft should cancel each other out within 1 degree

What two rules should you remember when a transaxle has been disassembled and you are preparing for intermediate shaft bearing replacement?

1. Snap rings should not be reused and new ones should be installed 2. Bearings that pass inspection can be reused as long as they were removed with a puller and not driven off with a hammer

Name 3 facts about removing and installing axle shafts

1. The axle shaft seals should be replaced, not reused 2. The axle shaft should be stood straight up in a vertical position when removed 3. Some axles require a slide hammer to be removed

What are two reasons a manual car will not start or crank?

1. The clutch safety switch could have an open circuit 2. The clutch switch could be out of adjustment

When a vehicle is being checked for driveline vibration, what two things should be checked?

1. The drive shaft should be checked for proper phasing 2. Drive shaft runout should be checked

What are two things to remember when greasing a newly installed universal joint?

1. The universal joint should be greased until grease purges out of all four caps 2. Universal joints should be greased with lithium grease meeting NLGI grade 1 or 2.

What are two things to keep in mind when a vehicle with automatic locking hubs is being diagnosed for slow engagement?

1. Vehicles with automatic locking hubs require as much as a full tire rotation in a specified direction in order for the hub to engage and disengage 2. The driver does not have to leave the vehicle to engage the automatic locking hubs

What can cause excessive driveline angles?

A broken transmission mount