A3 Manual Drive
Train & Axles
A growling noise is heard while the clutch pedal is held partly down, and it stops when the pedal is fully released. Which of these could be the cause?
A rear drive axle was rebuilt with new bearings and now rumbles on deceleration. These readings were recorded during setup. Which measurement requires correction?
| Measurement | Reading | Specification |
|---|---|---|
| Ring gear backlash | 0.008 in. | 0.005–0.012 in. |
| Ring gear runout | 0.002 in. | 0.005 in. max |
| Pinion bearing preload | 6 in.-lb | 15–30 in.-lb |
| Differential case bore runout | 0.001 in. | 0.003 in. max |
The purpose of the synchronizer in a shift-on-the-fly transfer case is to:
A manual transmission jumps out of fourth gear under heavy acceleration. What is the MOST likely cause?
A manual transaxle is hard to shift with the engine running but shifts easily with the engine off. Technician A says worn blocking rings are the cause. Technician B says the clutch is not fully releasing. Who is right?
A front-wheel drive vehicle clicks during sharp low-speed turns in both directions. Which of these is the LEAST likely cause?
When bleeding a hydraulic clutch release system, the technician should:
A four-wheel drive vehicle has a clunk from the transfer case each time the driver reverses direction from a stop. What is the MOST likely cause?
Gear lubricant is leaking onto the inner edge of the right front tire on a front-wheel drive vehicle. Which of these could be the cause?
A limited-slip differential is being refilled after service. Technician A says a friction modifier may be required in the lubricant. Technician B says the axle should be road tested in tight turns to check for chatter. Who is right?
The reverse idler gear in a manual transmission is used to:
A rear-wheel drive vehicle vibrates above 50 mph. The front U-joint working angle measures 1.4 degrees and the rear measures 4.1 degrees. Which of these could be the cause?
A rear drive axle whines under acceleration but is quiet on coast. Any of these could be the cause EXCEPT:
A part-time 4WD vehicle binds during tight turns on dry pavement in 4HI. Technician A says this is normal without a center differential. Technician B says a stretched transfer case chain is the cause. Who is right?
When checking synchronizer blocking ring clearance during transaxle assembly, the technician should:
A manual transmission grinds going into gear. Clutch pedal free play measures 2.5 inches against a specification of 1.0 to 1.5 inches. Which of these could be the cause?
A manual transmission is hard to shift into every forward gear, and clutch operation checks normal. Which of these is the LEAST likely cause?
A four-wheel drive vehicle engages 4HI normally but will not engage 4LO. Which of these could be the cause?
To measure companion flange runout on a rear drive axle, the technician should:
A manual transaxle whines only in fourth gear. What is the MOST likely cause?
A dual-mass flywheel is being replaced with the clutch. Technician A says the secondary mass should be checked for rotational free play. Technician B says a dual-mass flywheel may be resurfaced on a flywheel grinder. Who is right?
The center support bearing on a two-piece drive shaft is used to:
A rear-wheel drive vehicle has a growl from the left rear that changes pitch when the vehicle is swerved gently from side to side at 30 mph. Which of these could be the cause?
A part-time four-wheel drive vehicle has a whine from the transfer case in 2HI that rises with vehicle speed. Which of these is the LEAST likely cause?
A manual transmission leaks lubricant at the extension housing. Technician A says a worn output shaft bushing can allow the seal to leak. Technician B says a plugged transmission vent can cause the seal to leak. Who is right?
Reading Your Results: A3 Manual Drive Train and Axles, Test 1
A score by itself only tells you whether you passed. What follows is how to read the questions you missed on this test. A3 rewards one habit more than any other subject: knowing which parts are turning, and which are loaded, at the exact moment the noise appears.
If you missed the noise and vibration questions
Most of the diagnostic questions on this test are decided by when the noise happens rather than by what it sounds like, because every component in a drive train turns at a different speed and carries load only under certain conditions. A growl with the clutch pedal partly down that stops when the pedal is released is the release bearing, because that is the only moment it is loaded and spinning. A whine in one gear and no others has to be that gear set, since bearings and lubricant affect every gear. A growl from one corner that changes pitch as the vehicle is swerved is a wheel bearing, because swerving shifts weight onto and off that bearing. A whine from the transfer case in 2HI cannot be the chain, since the chain sits still until 4WD is engaged. Before choosing an answer, ask what is turning and what is carrying load in the exact condition described.
If you missed the questions built on a measurement
Three questions here give you readings against a specification, and each one is asking whether you know what that measurement controls.
If you missed the EXCEPT and LEAST likely questions
Four appear on this test, and missing more than one is a reading habit rather than a knowledge gap. Work out what the three real causes share before hunting for the odd one. On the clicking-during-turns question, three answers all involve an outer CV joint that is loaded and articulating in a turn, and one is an inner joint that is loaded in a straight line instead. On the drive-side axle whine question, three answers all affect how the ring and pinion teeth mesh under power, and one affects sealing rather than mesh. Naming the shared trait first turns four options into a single check.
If you missed the component function questions
The three component questions here all describe a part that exists to solve one specific problem. A transfer case synchronizer matches front and rear output shaft speeds so the mode collar can engage while the vehicle is moving. A reverse idler adds a third meshing gear to the train, and that extra mesh is what reverses output shaft rotation. A center support bearing carries the rear of the front shaft section and damps driveline vibration through its rubber insulator. On the exam these questions are asking what stops working when that function is lost, which is why a worn center support shows up as a rumble at a specific road speed rather than as a part that simply broke.