Free ASE Transit Bus Drive Train (H3) Test Practice Questions

Sample Practice Questions

Try these 10 sample questions from the ASE Transit Bus Drive Train (H3) Test practice bank. Each includes the answer and explanation. Continue with the interactive practice above to review the full question set.

1. 1A transit bus with an Allison automatic transmission has a satisfactory cold dipstick reading after refill. What is required before accepting its fluid level for extended operation?

   1. A.Accept the cold reading after the engine is shut down.
   2. B.Verify the level with a hot check at operating temperature.Correct answer: B
   3. C.Fill above the cold band to allow for fluid expansion.
   4. D.Verify the level with the bus parked on an incline.

   Explanation: The manual states, "DO NOT operate the transmission for extended periods of time until a Hot Check has verified proper fluid level." A satisfactory cold reading permits warming the unit; it does not replace the hot check.

   Reference: Prevost PA1621 Maintenance Manual — Section 07: Transmission — p. 9, Cold Check caution immediately before the hot-check instructions

2. 2A bus with a Dana universal joint has 0.008 inch of yoke movement horizontally relative to its bearing cups. What repair does Dana's inspection criterion require?

   1. A.Retain the joint because the limit is 0.012 inch for every joint.
   2. B.Add grease and accept the joint without further measurement.
   3. C.Retain the joint if its vertical movement is less than 0.006 inch.
   4. D.Replace the joint because either-direction movement exceeds 0.006 inch.Correct answer: D

   Explanation: Dana states, "If looseness is greater than .006” (.15mm) in either direction the UJ must be replaced". The 0.008-inch horizontal reading exceeds that threshold even if vertical movement is smaller.

   Reference: Dana Service, Parts & Maintenance Information Book — p. 20, Universal Joint Inspection

3. 3While investigating a noisy Meritor single-reduction axle carrier, a technician finds drive-pinion end-play looseness. What does the diagnostic flowchart indicate?

   1. A.The looseness proves the axle-housing breather is blocked.
   2. B.The looseness may indicate damage to the pinion bearings.Correct answer: B
   3. C.The looseness is the normal method of establishing gear backlash.
   4. D.The looseness confirms that the differential case is properly preloaded.

   Explanation: The flowchart states, "Any end play looseness indicates possible bearing damage." This is a reason to investigate the bearings, not proof of a blocked vent or acceptable gear adjustment.

   Reference: Meritor TP-99125 — Forward and Rear Axle Carrier Diagnostic Flowcharts — p. 8, Rear Tandem or Single Carrier — Differential Making Noise, drive-pinion end-play step

4. 4A transit bus develops erratic Allison transmission shifts immediately after its fluid was filled above the specified level. Which mechanism explains why the overfill should be corrected?

   1. A.Overfill raises clutch apply pressure in proportion to extra fluid.
   2. B.Overfill prevents aeration by keeping rotating parts submerged.
   3. C.Overfill can aerate fluid and disrupt hydraulic transmission operation.Correct answer: C
   4. D.Overfill improves cooling enough to prevent an erratic-shift complaint.

   Explanation: The manual states, "If fluid level is too high, the fluid can aerate, causing the transmission to shift erratically or overheat." Excess quantity does not provide a proportional apply-pressure adjustment or a guarantee against aeration or overheating.

   Reference: Prevost PA1621 Maintenance Manual — Section 07: Transmission — Section 07, p. 11, 3.3.1 Importance of Proper Fluid Level

5. 5A newly installed Dana center bearing repeatedly moves out of its rubber isolator. Inspection finds that the isolator is not perpendicular to the coupling shaft. What cause does Dana identify?

   1. A.Misalignment of the rubber isolator can dislodge the bearing.Correct answer: A
   2. B.A perpendicular isolator would prevent normal bearing rotation.
   3. C.The metal bracket must be parallel to the shaft in every plane.
   4. D.The bearing must be intentionally loose within the rubber cushion.

   Explanation: Dana states, "Misaligned rubber isolators can cause the bearing to dislodge from the rubber isolator causing damage and premature failure". The rubber isolator, rather than bracket appearance alone, must have the prescribed alignment.

   Reference: Dana Service, Parts & Maintenance Information Book — p. 19, Self Aligning Centre Bearing Installation

6. 6A Meritor drive axle overheats after service, and its lubricant level is confirmed above specification. Which first correction addresses the documented oil-level cause before temperature is reassessed?

   1. A.Retain the overfill because extra oil increases heat capacity.
   2. B.Lower fluid below specification to minimize churning losses.
   3. C.Keep the overfill and substitute lower-viscosity gear lubricant.
   4. D.Correct the overfill to specification, then reassess temperature.Correct answer: D

   Explanation: Under overheating causes, Meritor lists, "Lubricant is added over the assembly’s fill line during maintenance procedures." Correcting the confirmed overfill addresses that cause. Underfilling, retaining excess oil, or substituting viscosity for level correction does not restore the specified condition.

   Reference: Meritor TP-0445 — Parts Failure Analysis — Section 4, pp. 32–33, Components Overheat During Operation — How Overheating Can Occur

7. 7Ethylene glycol contamination is confirmed on the friction clutch plates of a transit bus Allison transmission. During the required teardown and cleaning, how should those plates be treated?

   1. A.Replace the contaminated friction clutch plates.Correct answer: A
   2. B.Wash the plates and reuse them if thickness is correct.
   3. C.Dry the plates and reuse them if no cracks are visible.
   4. D.Retain the plates and shorten the next fluid interval.

   Explanation: The manual states, "Friction clutch plates contaminated with ethylene glycol must be replaced." Washing, drying, or shortening a service interval does not meet this replacement requirement.

   Reference: Prevost PA1621 Maintenance Manual — Section 07: Transmission — Section 07, p. 12, 3.3.5 Coolant Leakage

8. 8A Dana 10 Series driveshaft has vibration accompanied by excessive looseness between the mating slip-assembly components. What repair does Dana specify?

   1. A.Replace only the dust cap and leave the worn mating parts.
   2. B.Increase grease pressure until spline looseness disappears.
   3. C.Replace all of the slip-assembly components.Correct answer: C
   4. D.Tighten the universal-joint straps to remove spline clearance.

   Explanation: Dana states, "If there is excessive looseness between the mating components, with the presence of vibration, all slip assembly components should be replaced (10 Series only)". The model and both symptoms are included; seals, grease, or U-joint strap torque do not correct worn mating splines.

   Reference: Dana Service, Parts & Maintenance Information Book — p. 21, Slip Assembly Inspection

9. 9A noisy Meritor hypoid axle has crow's-footing wear on both ring and pinion gears, with black lubricant and a burned odor. Which failure mechanism does Meritor associate with this combination?

   1. A.Insufficient lubricant or depleted EP additives allowing damaging contact.Correct answer: A
   2. B.Backlash adjustment alone despite adequate, thermally sound lubricant.
   3. C.Water-caused etching without thermal deterioration of the lubricant.
   4. D.Normal break-in polishing with clean, correctly specified lubricant.

   Explanation: Meritor states that crow's footing on the hypoid gears "indicates a low lubricant level or lubricant with depleted extreme pressure (EP) additives." The black, burned oil supports this lubrication-failure pattern rather than normal polishing, a backlash-only issue, or water-only etching.

   Reference: Meritor TP-0445 — Parts Failure Analysis — Section 4, p. 39, Hypoid Ring and Drive Pinion Gears

10. 10A transit bus Allison transmission sump contains metal particles beyond the minute particles normally trapped by the filter. What service decision does this finding support?

    1. A.Replace the filter and return the bus to service.
    2. B.Drain only enough fluid to remove visible particles.
    3. C.Add fresh fluid and check for particles next interval.
    4. D.Disassemble the transmission to identify the damage.Correct answer: D

    Explanation: The manual states, "When these particles are found in the sump, the transmission must be disassembled and closely inspected to find the source." This finding calls for investigation of internal damage rather than a fluid-only correction.

    Reference: Prevost PA1621 Maintenance Manual — Section 07: Transmission — Section 07, p. 11, 3.3.4 Metal Particles