Michigan SOS mechanic test

Heavy-Duty Drive Train

Heavy-Duty Drive Train is one of the 20 Secretary of State mechanic certification tests. Here's what the test covers, according to the state's published outline.

Topic guide · questions soon

What's on the test

Official topicWeight
Clutch components and diagnosis
  • Causes of hard shifting
  • Clutch pedal free play
  • Slipping clutch
  • Clutch “chatter”
  • Clutch brake
  • Pilot bearing
  • Clutch adjustment
19%
Driveshaft components and diagnosis
  • Driveline angles
  • Driveshaft disassembly
  • Driveline vibration
  • U-Joint replacement
  • U-joint maintenance
17%
Axle components and diagnosis
  • Ring and pinion backlash
  • Inter-axle differential lock
  • Pinion bearing preload
  • Differential side bearing preload
18%
Transmission components and diagnosis
  • Torque converter operation
  • Planetary gears
  • Causes of hard shifting
  • Automated mechanical transmission
  • Scan tool operation
  • Overdrive / underdrive
  • Transmission fluid condition
  • Clutch disc springs
  • Transmission / clutch noise
46%

Source: SOS Mechanic Testing Categories Overview (PDF). Test format: most SOS mechanic tests have 55 questions, and a few have 65–100 (SOS FAQ). Passing scores vary by test; your result letter shows the passing score and your score.

Practice questions coming soon

The Heavy-Duty Drive Train practice bank is being written to the official outline below. The All-Mechanic pass will include it when it launches.

Banks available now: Engine Repair · Front End, Suspension & Steering · Brakes & Braking Systems · Electrical Systems · Engine Tune-Up & Performance

Test-day facts

Source: michigan.gov/sos mechanic testing

Heavy-Duty Drive Train test FAQ

How many questions are on the Michigan Heavy-Duty Drive Train test?

The Secretary of State says most mechanic tests have 55 questions and a few have 65 to 100. The test is “quick pass,” so it ends as soon as you reach the minimum passing score.

What topics are on the Heavy-Duty Drive Train test?

The SOS Mechanic Testing Categories Overview lists: Clutch components and diagnosis (19%), Driveshaft components and diagnosis (17%), Axle components and diagnosis (18%), Transmission components and diagnosis (46%).

How much does the test cost, and where do I take it?

Each mechanic test costs $18 (effective July 1, 2026). Tests are taken on a touch-screen kiosk at any Secretary of State office; pre-register and schedule through SOS Online Services. Approved automotive schools can also test their students.

Are these the real test questions?

No. MI Trade Prep questions are original practice items written to the official topic outline. They are not actual exam questions, and MI Trade Prep is not affiliated with the Michigan Department of State.

Sources: SOS mechanic testing · SOS mechanics page · SOS mechanic FAQ