Tennessee CDL Combination Test (TN) 2026

5 out of 5 (68 votes)
80% Passing score
20 Questions
4 Mistakes allowed
Preparing for your Commercial Driver's License (CDL) combination vehicles endorsement has never been easier with our Tennessee CDL combination test. This comprehensive tool is designed to help you master all key areas necessary for safe and effective driving of combination vehicles. Our TN DMV practice test includes a variety of multiple-choice questions covering critical topics such as coupling and uncoupling, pre-trip inspections, driving techniques, backing and maneuvering, and air brake systems. Each combination CDL practice test consists of 20 questions, requiring you to get at least 16 correct answers to pass. You'll gain an understanding of essential topics like the increased stopping distances required for combination vehicles due to their greater weight. Mastering these concepts is crucial for maintaining safety on the road and ensuring you can handle the unique challenges presented by these larger, heavier vehicles. One of the standout features of our Tennessee permit practice test is the flexibility it offers. There are no time limits, allowing you to spend as much time as you need on each question. This means you can fully absorb the material and understand each concept without feeling rushed. Moreover, the practice permit test is available online 24 hours a day, 7 days a week. This convenience allows you to study and take the test at a time that fits your schedule, rather than being restricted by the availability of a driving school. Our TN combination CDL test is tailored specifically to the driving laws and regulations of Tennessee. As driving laws vary from state to state, this ensures that you're studying the most relevant and accurate information for your CDL combination vehicles endorsement. Understanding TN's specific rules, regulations, and road signs is vital for your success on the DMV permit test practice and for your safety on the road. Whether you're a seasoned driver or new to the world of commercial driving, our Tennessee permit test practice is designed to provide you with the knowledge and confidence you need. Start your preparation today with our comprehensive and flexible combination vehicle test.
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Sample Tennessee Combination Test Questions

Question 1

After supplying air to a trailer, how should you check for crossed air lines and verify brake operation?

  1. A Lift the brake pedal and watch the pressure gauge
  2. B Shut off the engine, apply and release the trailer brakes, and listen
  3. C Set only the tractor parking brakes from the cab
  4. D Release the tractor brakes and immediately pull forward

Correct answer: B – Shut off the engine, apply and release the trailer brakes, and listen

After the trailer air system reaches normal pressure, shut off the engine so the brakes can be heard clearly. Apply and release the trailer brakes; listen for movement during application and escaping air during release. The Tennessee coupling procedure uses this check before the tractor is backed fully under the trailer.

Source: Tennessee Commercial Driver’s License Manual — § 6.4.1, “Coupling Tractor-Semitrailers,” Step 8

Question 2

During the coupling inspection, the fifth-wheel locking lever is not in the locked position. What should you do?

  1. A Release the parking brakes and drive slowly
  2. B Replace the entire fifth wheel immediately
  3. C Correct the coupling problem before driving
  4. D Move the sliding fifth wheel to balance the load

Correct answer: C – Correct the coupling problem before driving

The locking lever must be in the locked position, and the safety latch must be properly placed over it when applicable. If these conditions are not met, the coupling is not secure. Do not drive the coupled unit until the problem has been corrected.

Source: Tennessee Commercial Driver’s License Manual — § 6.4.1, “Coupling Tractor-Semitrailers,” Step 13

Question 3

After a tractor-semitrailer is coupled, how much visible space should remain between the upper and lower fifth wheel?

  1. A About 1 to 2 inches
  2. B About 2 to 5 inches
  3. C At least 5 inches
  4. D No visible space

Correct answer: D – No visible space

There should be no visible space between the upper and lower fifth wheel after coupling. A gap can indicate that the kingpin is resting on top of closed locking jaws instead of being secured by them. Inspect underneath to confirm that the jaws are closed around the kingpin shank and the locking mechanism is engaged.

Source: Tennessee Commercial Driver’s License Manual — § 6.4.1, “Coupling Tractor-Semitrailers,” Step 13

Question 4

What are the two functions of a combination vehicle's trailer emergency air line?

  1. A Improving fuel economy and cooling the brakes
  2. B Inflating the tires and reducing tread wear
  3. C Supplying the trailer air tanks and controlling the emergency brakes
  4. D Operating the lights and simplifying coupling

Correct answer: C – Supplying the trailer air tanks and controlling the emergency brakes

The emergency or supply line delivers air to the trailer's air tanks and controls its emergency brakes. A loss of pressure in this line causes the trailer emergency brakes to apply. The Tennessee manual also explains that loss of emergency-line pressure causes the tractor protection valve to close.

Source: Tennessee Commercial Driver’s License Manual — § 6.2.4, “Trailer Air-lines”

Question 5

Why should the trailer hand brake not be used to straighten a trailer that is jackknifing?

  1. A The hand brake cannot operate the trailer brakes
  2. B The trailer's locked braking wheels caused the skid
  3. C The hand-brake control cannot be reached during a skid
  4. D The hand brake automatically applies the tractor brakes

Correct answer: B – The trailer's locked braking wheels caused the skid

A trailer jackknife begins when the trailer wheels lock and the trailer swings outward. Applying the trailer hand brake continues braking the wheels that caused the skid. Release the brakes to regain traction; once the trailer wheels grip the road again, the trailer can begin following the tractor and straightening out.

Source: Tennessee Commercial Driver’s License Manual — § 6.1.5, “Prevent Trailer Skids”

Question 6

During normal driving, which braking method presents less danger of causing a trailer skid or jackknife?

  1. A Use the foot brake and reserve the trailer hand valve for brake testing
  2. B Apply only the trailer hand valve when slowing
  3. C Use the parking brakes for routine stops
  4. D Brake only the trailer while traveling through curves

Correct answer: A – Use the foot brake and reserve the trailer hand valve for brake testing

The foot brake sends air to all brakes on the combination vehicle, including the trailer brakes. This presents less danger of causing a skid or jackknife than applying only the trailer hand valve. The hand valve should be used to test the trailer brakes, not for normal braking while driving.

Source: Tennessee Commercial Driver’s License Manual — § 6.2.1, “Trailer Hand Valve”

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