Five free practice questions on manual drive train and axles: content area C of the ASE G1 Auto Maintenance & Light Repair test, 6 of its 55 scored questions (10.9%). They are in the ASE format: four options, one best answer. Answer each one before opening the explanation. No account, no email.
01The questions
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A front-wheel-drive car's manual transaxle, shifted through an external rod linkage, jumps out of fourth gear when the driver lifts off the throttle. Technician A says worn bushings in the shift linkage could be the cause. Technician B says worn or broken engine and transaxle mounts could be the cause. Who is right?
- A only
- B only
- Both A and B
- Neither A nor B
Show the answer
C. Correct. Technician A is right because worn bushings let slack into the linkage, so the gear may not engage fully, and Technician B is right because a worn mount lets the engine and transaxle rock on deceleration, moving the case against the linkage. Both are inspected and fixed before the transaxle's internal detents and gears are blamed.
Why not the others
A. Technician A is right, but so is Technician B. Worn linkage bushings can keep the sleeve from fully engaging the gear, and a mount that lets the engine and transaxle rock on deceleration moves the case against the linkage, which can pull the gear out too.
B. Technician B is right, but so is Technician A. Mounts that let the powertrain rock on deceleration can pull on the linkage, and worn linkage bushings add enough slack that the gear may not stay fully engaged; both are inspected.
D. Both technicians are right. Jumping out of gear is not only an internal fault: Technician A's worn linkage bushings and Technician B's worn or broken mounts can each pull the gear out or leave it partly engaged, and both are checked first.
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A two-piece drive shaft's center support bearing bracket has shims between it and the crossmember. What do these shims adjust?
- The slip yoke's depth in the transmission
- The center bearing's internal preload
- The universal joints' working angles
- The drive shaft's balance at speed
Show the answer
C. Correct. Shims under the bracket raise or lower the center bearing, and the height of that point sets the working angles of the universal joints on both shaft sections. They are refitted where they were found, and if a vibration points to the angles, the angles are measured against the manufacturer's specification before shims are changed.
Why not the others
A. The slip yoke's position in the transmission is set by the shaft's length and the axle's position, and shims that move the center bearing up or down do not change it. The shims set the height of the center bearing and so the universal joints' working angles.
B. A center support bearing is a sealed ball bearing in a rubber cushion, with no preload adjustment, and shims under its bracket do not load it. They move the bearing up or down, which changes the universal joints' working angles.
D. Drive shaft balance is set with weights on the tube and corrected on a balancer, not with shims at the center bearing. The shims set the bearing height, which sets the universal joints' working angles.
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A broken wheel stud is being replaced in a rear axle shaft flange with the shaft left in the vehicle. Each of these is correct practice EXCEPT:
- using a stud with the original's knurl diameter and thread size.
- driving the new stud in with a hammer on its threaded end.
- drawing the stud in with flat washers and a lug nut.
- checking that the stud's head sits flat against the flange.
Show the answer
B. Correct. Hammering on the threaded end damages the threads the lug nut needs and sends shock loads into the axle bearing, so the stud is pulled in instead. Flat washers over the stud and a lug nut turned onto it draw the knurl into the flange evenly until the head seats.
Why not the others
A. This is correct practice. The knurl has to match the original's diameter to grip the flange hole tightly, and the thread size must match the wheel's lug nuts; a smaller knurl would let the stud spin in the hole.
C. This is correct practice. Flat washers stacked over the stud and a lug nut turned onto it pull the knurl straight into the flange without hammer blows on the stud or the axle.
D. This is correct practice. A head that is not fully drawn in leaves the stud loose or cocked, so the technician checks that it sits flat against the back of the flange before the wheel goes on.
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A part-time four-wheel-drive (4WD) pickup has a floor-mounted lever that shifts its transfer case through an external rod linkage. The lever is very hard to move out of 4H. Any of these could be the cause EXCEPT:
- a bent shift rod rubbing against its bracket.
- driveline windup after driving in 4H on dry pavement.
- dry, corroded pivots in the shift linkage.
- an open circuit at the 4WD indicator lamp switch.
Show the answer
D. Correct. The indicator switch only tells the driver which range is engaged by lighting the lamp; an open in its circuit leaves the lamp dark but puts no load on the lever or the linkage. The other three each add resistance to the lever's movement.
Why not the others
A. This could cause it. A shift rod bent so that it rubs its bracket drags through its travel and stiffens the lever, so the linkage is inspected for bends and contact along its full length.
B. This could cause it. In 4H a part-time transfer case locks the front and rear drive shafts together, and on dry pavement the tires cannot slip to absorb the difference in their paths, so the driveline winds up and loads the shift parts; rolling a short distance straight ahead or in reverse usually frees it.
C. This could cause it. The linkage pivots depend on lubrication and bushings, and when they dry out and corrode, every movement of the lever takes more effort, including the shift out of 4H.
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A 4WD pickup was driven at highway speed and then straight into a creek deep enough to cover its front axle. A week later its front differential lube is milky tan, and the level is above the fill hole. How did the water most likely get in?
- Condensation from normal daily temperature swings
- Heat pressure in the housing forcing water in
- The hot housing cooling and drawing water in
- Gear oil absorbing moisture as brake fluid does
Show the answer
C. Correct. The highway drive heated the lube and the air above it, and plunging the hot housing into cold water made that air contract, pulling creek water in through the vent and past the seals. The unit is drained, flushed and refilled with the specified lube, the vent and seals are inspected, and any other driveline unit that was under water is checked as well.
Why not the others
A. Daily warm-ups and cool-downs condense only traces of moisture over a long time; they cannot raise the level above the fill hole in a week. The amount of water and its timing point to the creek crossing, when the hot housing cooled under water.
B. Pressure built in a hot housing pushes air and oil outward through the vent and past the seals; it cannot push water in. The water entered when the housing cooled suddenly in the creek and the air inside it contracted, drawing water in.
D. Glycol brake fluid absorbs moisture from the air, but gear oil does not soak up water that way, and no such absorption could raise the level above the fill hole. The water was drawn in when the hot housing cooled in the creek.
02Answer key
| Question | Answer |
|---|---|
| Q1 | C |
| Q2 | C |
| Q3 | B |
| Q4 | D |
| Q5 | C |
03What area C covers
This content area covers manual transmissions and everything that carries power to the wheels: hydraulic clutch systems, shift linkages, external seals and fluid checks, drive shafts, U-joints and CV joints, center bearings, wheel bearings and hubs, rear axle housings, vents and wheel studs, transfer cases, and four-wheel and all-wheel drive checks, including tire size and wear.
The ASE test specification calls this content area “Manual Drive Train and Axles”. It carries 6 of the 55 scored questions, 10.9% of the test.
- Service and bleed hydraulic clutch systems
- Inspect mounts, shift linkages and external seals
- Check and refill transmission, axle and transfer case fluid
- Inspect drive shafts, U-joints, CV joints and center bearings
- Service wheel bearings, seals, hubs and wheel studs
- Inspect axle housings, vents and mountings
- Check 4WD and AWD operation and tire matching
- Road test for drive train noise and vibration
04What the questions turn on
Plugged vents push oil out
Driving heats the axle lube and the air above it, and the vent lets that air out. With the vent plugged, pressure pushes oil past every seal at once, worst after highway driving. The vent is cleared before new seals go in.
Match the vibration to a part
Drive shaft speed is tire speed times the axle ratio. When a vibration analyzer's frequency matches drive shaft speed, not tire or engine speed, the drive shaft is the source, for example a shaft that is out of balance.
The right lube for the job
Gear oil much thicker than specified slows the synchronizers, so shifts are stiff and can clash in cold weather. A limited-slip differential refilled without its friction modifier chatters in tight turns. The fix is the specified fluid and additive.
AWD tires must match
Unequal tire diameters make the front and rear axles turn at different speeds, so an all-wheel-drive manufacturer limits tread depth differences. A single new tire may need to be shaved to match the others, or the tires replaced as a set.
05The other content areas
The G1 test has seven content areas. Each has its own page of free questions:
The ASE G1 Auto Maintenance & Light Repair practice test page describes the full question bank. How these questions are written and checked: how our questions are made. Found a mistake? Tell us and we will fix it.
ToolboxPrep is an independent study site. It is not affiliated with or endorsed by ASE (the National Institute for Automotive Service Excellence). Our questions are original practice questions written to the published ASE test specifications; they are not actual test questions.