Hard steering both directions

Low fluid, weak pump, low tire pressure, binding linkage/kingpins

Heavier in one direction only

Fault in the steering-gear control valve

Whining pump after service

Air trapped in the system — bleed/burp it; check fluid level

Foamy / aerated fluid

Air being drawn in — low fluid or a suction-side leak

Poor return to center

Insufficient positive caster, binding kingpins/column, tight gear, low pressure

Excessive free play / wander

Worn tie-rod & drag-link ends, worn gear, loose wheel bearings

Sagged / broken leaf spring

Low ride height, pull, uneven tire wear, axle shift

Broken spring center bolt

Axle shifts → thrust-angle error, dog-tracking, pull

Leaking air spring (bag)

Truck leans / sits low on that side

Continued bounce, brake dip, tire cupping

Worn 5th-wheel jaws / excess play

Loose, unsafe coupling; kingpin movement

Twisted / cracked frame

Axle misalignment, handling problems (often from overload)

Unequal caster side-to-side

Pull toward the side with less (more negative) caster; poor return

Excessive / unequal camber

Wear on one tire edge; pull toward the more-positive side

Rapid feathered (saw-tooth) front-tire wear

Off-center steering wheel

Crooked steering wheel driving straight — often a thrust-angle issue

SAI / turning-radius error

Not adjustable — indicates a bent steering arm, spindle, or axle

What are the four ASE T5 content areas?

ASE T5 covers four content areas: Steering System Diagnosis and Repair (14 scored questions), Suspension, Frame, and 5th Wheel Diagnosis and Repair (19), Wheel Alignment Diagnosis, Adjustment, and Repair (16), and Wheels, Tires, and Hub Diagnosis and Repair (11).

What is the passing score for the ASE T5?

There is no fixed percentage. Raw scores are converted to a scaled score, and a panel of truck-service subject-matter experts sets the passing standard for each test form so the bar stays consistent even as question difficulty varies. Your overall scaled score, not any single content area, decides pass or fail.

How is the ASE T5 test delivered?

The T5 test is computer-based and delivered by appointment at a Prometric testing center. You register through your myASE account, schedule the appointment, and typically have 90 days from purchase to test. If you fail, you must wait 30 days before retaking and pay the test fee again.

What experience do I need to get ASE T5 certified?

ASE requires about two years of relevant hands-on work experience, or one year of experience plus a two-year degree in a related field, to earn the certificate. You may pass the test first; ASE holds your result and issues the certification once you document the required experience.

How long is ASE T5 certification valid and how do I renew it?

ASE T5 certification is valid for five years. You recertify by passing the shorter current T5 recertification test, or, where eligible, by using the ASE Renewal App, which delivers smaller sets of questions over time instead of one sit-down test.

What is a 'Technician A / Technician B' question?

It is the signature ASE format: two technicians each make a statement, and you choose whether Technician A only is correct, Technician B only, both, or neither. Judge each statement separately as true or false, then pick the answer that matches — do not let a true statement A make you overlook a false statement B.

How should I use this ASE T5 study guide?

Work through the four content areas, giving extra time to Suspension/Frame/5th Wheel and Wheel Alignment since they carry the most scored questions. After each area, take the checkpoint quiz to find gaps, drill them with our free practice questions and flashcards, and revisit the diagrams and worked scenarios before test day.

Is this ASE T5 study guide free?

Yes — the full guide, the checkpoints, the glossary, the practice questions, and the flashcards are 100% free, with no account required.

What is the difference between caster, camber, and toe?

Caster is the forward/rearward tilt of the steering axis viewed from the side and controls straight-line stability and steering return. Camber is the inward/outward tilt of the wheel viewed from the front. Toe is the difference between the front and rear of the tires viewed from above. On a solid front axle, toe is usually the only routinely adjusted angle; incorrect toe causes rapid, feathered tire wear. Unequal caster or camber side-to-side makes the truck pull; SAI and turning radius are diagnostic, not adjustable.

What causes a heavy-duty truck to pull to one side while driving?

A truck pulls toward the side with less (more negative) caster, the side with more positive camber, or the side with the lower tire pressure. Other causes include a dragging brake, a bent axle or steering arm, road crown, and uneven loading. Check tire pressure and ride height first — a low tire or sagging air bag mimics an alignment pull. If the pull reverses when you swap front tires side-to-side, a tire (radial pull) is the cause, not alignment.

What does the steering wheel returnability tell you about a steering system?

After a turn, the wheels should self-center and the steering wheel return toward straight ahead. Poor return points to insufficient positive caster, binding kingpins or ball joints, a tight or dry steering gear, low tire pressure, or a binding steering shaft and U-joints. Positive caster and steering-axis inclination are what create the self-centering force. This is a Steering System diagnostic skill — distinguish a binding component from an alignment angle that is out of spec.

What is the difference between manual, hydraulic, and integral power steering?

Manual steering uses only the driver's effort through the gear. Hydraulic power steering adds a pump-driven cylinder to assist. An integral gear combines the steering gear and the hydraulic assist in one unit, while a linkage-type system uses a separate power cylinder on the steering linkage. Most medium/heavy trucks use an integral (recirculating-ball) power-steering gear with hydraulic assist. Hard steering can come from low fluid, a weak pump, a worn gear, low tire pressure, or binding linkage.

What is excessive steering free play and how is it diagnosed?

Steering free play (lash) is the amount the steering wheel turns before the front wheels move. Excessive play comes from worn tie-rod and drag-link ends, a loose or worn steering gear, worn kingpins, or loose wheel bearings, and causes wander and reduced control. Diagnose with a dry-park (turning) test and a pry-bar check to feel which joint or component is loose. Adjust the steering-gear sector lash only after the linkage and gear mesh are confirmed good — over-adjusting binds the gear on center.

How does a truck air (air-ride) suspension system work?

An air suspension replaces steel springs with air springs (bags). A height-control valve senses ride height at the axle and adds or exhausts air to hold the frame level as load changes, while shock absorbers dampen the motion. The truck's air system supplies the regulated pressure. A leaking air bag or a stuck/misadjusted height-control valve makes the truck lean or sit low on one side. Always set ride height to spec before measuring alignment — wrong ride height throws off the angles.

What is a walking-beam suspension and where is it used?

A walking-beam (equalizing-beam) suspension is a tandem-axle design where a rigid beam pivots on a center saddle, connecting the two axles so the load equalizes between them as the truck travels over uneven ground. It is common on heavy off-highway and vocational trucks for traction and durability. Worn beam center bushings and end bushings cause axle misalignment, tire wear, and noise. Other heavy-truck suspensions include multi-leaf springs and air ride; each carries and locates the axle differently.

What is the purpose of the 5th wheel and how is it inspected?

The 5th wheel is the coupling on the tractor that locks onto the trailer's kingpin, carrying the trailer's load and allowing it to pivot. It is inspected for worn or cracked locking jaws, excessive fore-and-aft (kingpin-to-jaw) play, proper lubrication, secure mounting, and correct lock engagement. Excessive jaw wear or play lets the kingpin move and can cause an unsafe coupling — adjust or replace the locking mechanism. Keep the 5th-wheel plate greased; a dry plate causes hard steering, chatter, and uneven plate wear.

What is leaf-spring sag and how does it affect a truck?

Leaf-spring sag is the loss of arch in a multi-leaf spring from fatigue or overloading, which lowers ride height on that corner. It changes alignment angles, reduces load capacity and ride quality, and can cause the axle to shift, leading to a pull and uneven tire wear. Measure ride height side-to-side; a sagged or broken spring (or a broken center bolt that lets the axle move) is a common cause. A broken center bolt also lets the axle shift, throwing off thrust angle — check it when an axle is misaligned.

What is thrust angle and why does it matter on a truck?

Thrust angle is the direction the rear (or tandem) axle actually points relative to the frame centerline. When the axle is not square to the frame, the truck 'dog-tracks,' the steering wheel sits off-center to drive straight, and the tires wear — a common cause of unexplained pull and wander. On a tandem, both drive axles must be parallel and square; a shifted axle (broken spring center bolt, worn bushings) is the usual cause. A thrust-angle alignment squares the rear axle first, then sets front toe to the thrust line.

What causes feathered (saw-tooth) tire wear on a truck's front tires?

Feathered wear — a saw-tooth edge you can feel by running a hand across the tread — is caused by incorrect toe. Excessive toe-in or toe-out scrubs the tire sideways as it rolls, shaving one side of each tread rib. It is the number-one cause of rapid front-tire wear on a truck. Distinguish it from one-edge wear (camber) and both-edge wear (under-inflation). Worn tie-rod ends or a bent steering arm can also let toe wander even when set correctly.

What causes tire cupping (scalloped wear) on a heavy truck?

Cupping is a series of scalloped dips around the tread, caused by the tire bouncing as it rolls instead of staying planted. The usual causes are worn shock absorbers, loose or worn wheel bearings, an out-of-balance wheel assembly, or a bent rim — anything that lets the tire hop. This is a Wheels/Tires/Hub diagnostic clue: cupping points to a bounce problem, not alignment. Fix the cause (shocks, bearings, balance) and rotate or replace the cupped tire — the pattern will not smooth itself out.

How should heavy-truck wheel bearings be adjusted and serviced?

Adjustable (tapered roller) wheel bearings are cleaned, inspected, and packed with the specified grease, then adjusted: seat the bearing by torquing the nut while rotating, back it off, then re-torque to the light final spec to set end play (typically about 0.001–0.005 in.). Over-tight bearings run hot and fail. A hub running hotter than its mates points to over-tight or dry bearings, or a dragging brake — investigate before it seizes. Many modern trucks use preset (unitized) hub assemblies that are torqued to a fixed spec, not manually adjusted.

What does a high-speed steering-wheel vibration usually indicate?

A vibration that increases with road speed usually comes from the tire-and-wheel assemblies — an out-of-balance wheel, an out-of-round (radial runout) tire, a bent rim, or a damaged tire. Loose wheel bearings and worn steering/suspension parts can amplify it into a shimmy at the steering wheel. Check tire/wheel balance and runout first; balance the assembly and correct excessive runout before chasing other parts. A shimmy that comes and goes can be a worn kingpin, tie-rod end, or shock — inspect the linkage too.

Why is correct tire inflation critical on a heavy truck?

Inflation must match the load. Under-inflation overheats the tire and wears both shoulders; over-inflation wears the center and harms traction. On dual wheels, the two tires must be matched in pressure and diameter, or the larger/harder tire carries the load and wears unevenly while the other scuffs. Set pressure cold to the load/inflation table for the actual axle load — not just to the sidewall maximum. Mismatched duals are a classic cause of inner-tire wear and premature failure.

What is the difference between bump steer and memory steer?

Bump steer is an unwanted change in toe (the wheels steer themselves) when the suspension moves over a bump, usually from worn parts or incorrect ride height that changes the tie-rod geometry. Memory steer is the truck wanting to keep turning the way it was last steered, often from a binding ball joint, kingpin, or steering shaft. Both feel like a steering complaint but have different roots — geometry/ride height vs. a binding pivot. Correct ride height and replace binding pivots; verify alignment after the repair.

The ASE Suspension & Steering certification test for medium/heavy trucks, part of the Truck (T-series) program from the National Institute for Automotive Service Excellence. It certifies a technician's ability to diagnose and repair heavy-truck steering, suspension, alignment, and wheel/tire systems.

The forward or rearward tilt of the steering axis (kingpin) viewed from the side. Positive caster aids straight-line stability and steering return; unequal caster side-to-side causes a pull.

The inward or outward tilt of the wheel viewed from the front. Positive camber leans the top of the tire outward. Excessive camber wears one edge of the tire; unequal camber causes a pull.

The difference between the front and rear of a pair of tires viewed from above (toe-in or toe-out). Incorrect toe is the leading cause of rapid, feathered front-tire wear; it is usually the only routinely adjusted front angle on a solid axle.

Steering axis inclination (SAI)

The inward tilt of the kingpin/steering axis viewed from the front. With camber it sets the scrub radius and helps the wheels self-center. SAI is a diagnostic angle — it is not adjustable, so a change indicates a bent part.

Turning radius (toe-out on turns)

The geometry (Ackermann) that makes the inner wheel turn sharper than the outer through a corner. Built into the steering-arm angle; an error means a bent steering arm.

The direction the rear (or tandem) axle actually points relative to the frame centerline. A non-zero thrust angle causes dog-tracking, an off-center steering wheel, and tire wear.

When the rear axle does not follow directly behind the front because of a misaligned (non-square) axle, so the truck travels slightly crab-wise.

FREE ASE T5 Study Guide 2026 + Quizzes & Readiness Score

This free ASE T5 study guide teaches to the certification test — every content area the National Institute for Automotive Service Excellence tests on medium and heavy trucks, organized the way the exam is built.^[1]The T5 test certifies that you can diagnose and repair a truck’s steering, suspension and frame, wheel alignment, and wheel, tire, and hub systems — reading the symptom, running the right check, and making the correct repair.

The computer-based test has 70 questions (60 scored, 10 unscored research items) and 1 hour 15 minutes of testing time, spread across four content areas.^[2] It is hands-on: questions are written by working truck technicians and focus on practical diagnosis, often using the format. This guide is interactive, not a wall of text — each area has a built-in checkpoint quiz, hover-able glossary terms, worked diagnostic scenarios, and concept questions.

Read this guide content area by content area, test yourself at each checkpoint, then round out your free T5 prep with our practice questions and flashcards.

ASE T5 is one of the 29 ASE certifications — explore our ASE study guides to compare and prep across the whole family.

ASE T5 Exam Snapshot

ASE T5 Suspension & Steering at a glance (2026)
Detail	ASE T5 Suspension & Steering
Questions	70 administered (60 scored + 10 unscored research)
Time	1 hour 15 minutes of testing
Format	Multiple choice, computer-based by appointment (Prometric)
Content areas	4 (Suspension, Frame & 5th Wheel is the largest, ~32%)
Passing score	Scaled score; standard set per test by an expert panel (no fixed %)
Experience	~2 years relevant work experience (or 1 year + 2-year degree)
Cost	$62 test fee +$ 34 registration fee per order (fees can change)
Certification cycle	Valid 5 years; recertify via the T5 recert test or ASE Renewal App
Certifying body	ASE (National Institute for Automotive Service Excellence)

ASE T5 by content area (2026 — share of 60 scored questions)

Suspension, Frame & 5th Wheel

19 Qs · 32%

Wheel Alignment

16 Qs · 27%

Steering System

14 Qs · 23%

Wheels, Tires & Hub

11 Qs · 18%

Suspension, Frame & 5th Wheel and Wheel Alignment together are about 59%of the scored test — but every area is tested, so don’t skip the smaller ones.

Suspension, Frame & 5th Wheel and Wheel Alignment together are about 59% of the scored test, but every area is tested — don’t skip the smaller ones.^[1] Here is the official distribution of the 60 scored questions:

ASE T5 content areas (2026 — share of 60 scored questions)

Suspension, Frame & 5th Wheel32% · 19 Qs

Wheel Alignment27% · 16 Qs

Steering System23% · 14 Qs

Wheels, Tires & Hub18% · 11 Qs

This guide teaches all four content areas as four study modules. Before the areas, it helps to see the alignment angles that tie steering, suspension, and tire wear together:

Truck wheel-alignment angles you must know

CasterForward/rearward tilt of the steering axis (kingpin) viewed from the side. Positive caster aids straight-line stability and steering return. Unequal caster pulls toward the side with less (more negative) caster.
CamberInward/outward tilt of the wheel viewed from the front. Positive = top leans out. Excessive camber wears the tire on one edge; unequal camber pulls toward the more-positive side.
ToeDifference between the front and rear of the tires viewed from above. Incorrect toe is the #1 cause of rapid, feathered front-tire wear. Usually the only routinely adjusted front angle on a solid axle.
Steering axis inclination (SAI)Inward tilt of the kingpin/steering axis viewed from the front. With camber it sets the scrub radius and helps the wheels return to center; not adjustable — a change means a bent part.
Turning radius (toe-out on turns)The inner wheel turns sharper than the outer through a corner (Ackermann). Built into the steering-arm angle; an error here means a bent steering arm.
Thrust angle / axle alignmentThe direction the rear (or tandem) axle actually points vs. the frame centerline. A misaligned axle causes 'dog-tracking,' a crooked steering wheel, and tire wear.

On a solid-axle truck, toe is usually the only routinely adjusted front angle — but you must be able to read all of them.

1 · Steering System Diagnosis & Repair

About 23% of the scored test (14 questions). This area covers the heavy-truck steering system end to end — the gear, the hydraulic power assist, and the linkage — and how a fault in any of them shows up as a steering complaint.^[1]

A systematic steering-pull / wander diagnosis

1 · Verify & road-testConfirm the complaint — pull, wander, hard steering, shimmy, or poor return — and note speed, braking, and road crown effects.
2 · Check the easy stuffTire pressure and condition, ride height, and obvious leaks (power-steering fluid, air bags) before suspecting alignment or the gear.
3 · Inspect for play & wearDry-park / pry-bar check the kingpins, tie-rod and drag-link ends, steering gear, and wheel bearings for looseness.
4 · Measure alignmentOn level alignment equipment, read caster, camber, toe, SAI, and axle thrust angle against spec.
5 · Repair & re-verifyReplace worn parts, set ride height, adjust toe (and caster where adjustable), then road-test to confirm the pull is gone.

Rule out tire pressure and ride height first — a low tire or a sagging air bag mimics an alignment pull and wastes a rack of time.

Manual, Hydraulic & Integral Power Steering

Manual steering uses only the driver’s effort through the gear; hydraulic power steering adds a pump-driven assist. Most medium/heavy trucks use an gear that combines the gear and the assist in one unit, while a system puts a separate power cylinder on the linkage.

Steering Gear, Pump & Hydraulics

The supplies pressurized fluid; the gear converts the steering-wheel rotation into the back-and-forth motion of the linkage. A whining pump after a repair usually means air in the system— bleed it. Steering that is heavier in one direction than the other points to a fault in the gear’s control valve, not the pump.

Common steering-system complaints and likely causes
Complaint	Likely cause
Hard steering both directions	Low fluid, weak pump, low tire pressure, binding linkage/kingpins
Heavier in one direction only	Fault in the steering-gear control valve
Whining pump after service	Air trapped in the system — bleed/burp it; check fluid level
Foamy / aerated fluid	Air being drawn in — low fluid or a suction-side leak
Poor return to center	Insufficient positive caster, binding kingpins/column, tight gear, low pressure
Excessive free play / wander	Worn tie-rod & drag-link ends, worn gear, loose wheel bearings

Linkage, Free Play & Returnability

The , , and carry the gear’s motion to the wheels; worn ends or a worn gear cause and wander. Diagnose with a dry-park (turning) test and a pry-bar check to feel which joint is loose.

After a turn the wheels should self-center — poor returnability points to low caster or a binding pivot. Watch for (toe changes over bumps) and (binding pivot).

Checkpoint · Area 1 · Steering System

Question 1 of 10

During a road test, a technician notices that the steering wheel returns slowly to the center after a turn. What is the MOST likely cause?

2 · Suspension, Frame & 5th Wheel Diagnosis & Repair

About 32% of the scored test (19 questions) — the single biggest area. It covers what carries and locates the load: leaf and air springs, the walking beam, shocks, the frame, and the 5th-wheel coupling.^[1]

Leaf Springs & Walking Beam

A stack carries the load and locates the axle. Sag, broken leaves, or a broken lower ride height, change alignment, and can let the axle shift — a classic source of pull and tire wear. Heavy vocational trucks often use a tandem that equalizes load between the two axles; worn beam bushings cause misalignment and noise.

Air (Air-Ride) Suspension & Shocks

Follow the air-ride circuit to keep the parts straight:

How a truck air (air-ride) suspension levels itself

Air supply (governor)— The truck's air system feeds regulated pressure to the suspension circuit through the supply line.
Height control valve— Senses ride height at the axle and adds or exhausts air to hold the frame at the correct height as load changes.
Air springs (bags)— Replace steel springs; carry the load and cushion the ride. A leaking bag drops that corner and leans the truck.
Shock absorbers— Dampen spring/bag oscillation. Worn shocks let the truck keep bouncing after a bump.
Exhaust / level out— When the truck is loaded or unloaded, the height valve re-levels by adding or dumping air, then the loop holds.

A truck that leans or sits low on one side usually means a leaking air bag or a stuck/misadjusted height-control valve — set ride height before alignment.

A truck that leans or sits low on one side usually has a leaking or a stuck/misadjusted . let the truck keep bouncing after a bump and cause tire . Always set to spec before measuring alignment.

Frame & 5th Wheel

The is the truck’s backbone; twisting or cracks (often from overloading) misalign the axles. The locks onto the trailer kingpin — inspect the for wear, check fore-and-aft play, confirm secure mounting and proper lock, and keep the plate greased (a dry plate causes hard steering and chatter).^[5]

Suspension, frame & 5th-wheel faults and what they cause
Fault	Symptom
Sagged / broken leaf spring	Low ride height, pull, uneven tire wear, axle shift
Broken spring center bolt	Axle shifts → thrust-angle error, dog-tracking, pull
Leaking air spring (bag)	Truck leans / sits low on that side
Stuck/misadjusted height-control valve	Incorrect ride height on one corner; won't re-level
Worn shock absorbers	Continued bounce, brake dip, tire cupping
Worn 5th-wheel jaws / excess play	Loose, unsafe coupling; kingpin movement
Twisted / cracked frame	Axle misalignment, handling problems (often from overload)

Checkpoint · Area 2 · Suspension, Frame & 5th Wheel

Question 1 of 10

When diagnosing a heavy-duty truck with uneven tire wear, the FIRST component to inspect should be the:

3 · Wheel Alignment Diagnosis, Adjustment & Repair

About 27% of the scored test (16 questions) — the second-largest area. This is where steering, suspension, and tire wear meet: measuring the alignment angles, reading the tire, and squaring the axles.^[1]

Caster, Camber, Toe, SAI & Turning Radius

sets straight-line stability and return; is the wheel’s front-view tilt; and is the leading cause of rapid front-tire wear and usually the only routinely adjusted front angle. and are diagnostic angles — they aren’t adjustable, so an error means a bent part.

Alignment angle → effect on the truck
Angle out of spec	Effect
Unequal caster side-to-side	Pull toward the side with less (more negative) caster; poor return
Excessive / unequal camber	Wear on one tire edge; pull toward the more-positive side
Incorrect toe	Rapid feathered (saw-tooth) front-tire wear
Off-center steering wheel	Crooked steering wheel driving straight — often a thrust-angle issue
SAI / turning-radius error	Not adjustable — indicates a bent steering arm, spindle, or axle

Axle Alignment, Thrust Angle & Tandems

On a truck, the rear (or tandem) axles must be square to the frame. A misaligned axle creates a that makes the truck , sits the steering wheel off-center, and wears tires.

A shifted axle — from a broken or worn bushings — is the usual cause. A thrust-angle alignment squares the rear axle first, then sets front toe to that thrust line.

Checkpoint · Area 3 · Wheel Alignment

Question 1 of 10

A technician finds that a vehicle pulls to the right while driving. The steering system is otherwise functioning correctly. The MOST likely cause is:

4 · Wheels, Tires & Hub Diagnosis & Repair

About 18% of the scored test (11 questions). The tire is a free diagnostic gauge: its wear pattern, plus balance and bearing condition, ties the whole system together.^[1]

Tires, Inflation & Wear Patterns

Read the wear pattern and it points you straight at the cause:

Irregular tire-wear pattern → likely cause

Both edges worn (center OK)Under-inflation — too little air lets the shoulders carry the load. Set pressure to the load/inflation table.

Center worn (edges OK)Over-inflation — the crown carries the load. Reduce to the specified pressure.

One edge / inner or outer shoulderIncorrect camber (or a bent axle). Outer-edge wear = too much positive camber; inner-edge = too much negative.

Feathered / saw-tooth (run a hand across)Incorrect toe — the #1 cause of rapid front-tire wear on a truck.

Cupping / scalloped (dips around the tread)Worn shocks, loose wheel bearings, or imbalance letting the tire bounce.

The tire is a free diagnostic gauge — reading the wear pattern points you straight at inflation, camber, toe, or a bounce (shocks/bearings).

Correct inflation must match the load: under-inflation overheats the tire and wears both shoulders; over-inflation wears the center. must be matched in pressure and diameter, or the larger/harder tire overloads and the other scuffs — a classic cause of inner-tire wear.

Wheels, Bearings & Hubs

A vibration that increases with speed usually means an out-of-balance wheel, , or a bent rim — check and runout first. Adjustable are packed and set to a small end play; over-tight or dry bearings run hot.

A hub running hotter than its mates means over-tight or dry bearings or a dragging brake — investigate before it seizes. Lubricant leaking at a hub points to a failed hub seal or hub cap.

Checkpoint · Area 4 · Wheels, Tires & Hub

Question 1 of 10

A technician finds that the steering wheel vibrates while driving at highway speeds. The first component to inspect should be:

How to Use This Study Guide

A study guide is a map, not the whole territory — use it alongside hands-on shop experience and our free tools. Give the most time to the two heaviest areas (Suspension/Frame/5th Wheel and Wheel Alignment), and focus on the diagnostic reasoning the test rewards. Read every item carefully, judging each statement on its own before you answer.

A study loop that actually works

1
Read a content area here
Work through one area at a time — start with steering, then the larger suspension and alignment areas.
2
Take the checkpoint
The quick check at the end of each area exposes what didn't stick.
3
Drill the gaps
Send your weak area straight into the free practice questions and flashcards.
4
Test under exam conditions
Take full, timed practice sets and review every miss — especially the diagnostic reasoning.

How to read a “Technician A / Technician B” question

Many ASE T5 items give two technicians’ statements and ask who is right. Judge each statement separately as true or false, then map to the answer:

A. Technician A onlyStatement A is correct AND statement B is wrong.

B. Technician B onlyStatement B is correct AND statement A is wrong.

C. Both A and BBoth statements are correct on their own.

D. Neither A nor BBoth statements are wrong.

The trap is letting a true statement A make you ignore a false statement B. Evaluate both before you choose.

ASE T5 Concept Questions

Common suspension-and-steering concepts the T5 test actually measures — at least one per content area. Tap any card for a short, exam-ready answer backed by an authoritative source, then test yourself on them as flashcards.

ASE T5 Glossary

Quick definitions for the terms you’ll see most across the ASE T5 Suspension & Steering test:

5th wheel: The plate-and-jaw coupling on the tractor that locks onto the trailer's kingpin, carrying the trailer load and allowing it to pivot.
5th wheel locking jaws: The jaws that grip the trailer kingpin. Worn jaws or excessive fore-and-aft play create an unsafe coupling and must be adjusted or replaced.
Air spring (air bag): A rubber bellows filled with air that replaces a steel spring on an air-ride suspension. A leaking bag lowers that corner and leans the truck.
ASE T5: The ASE Suspension & Steering certification test for medium/heavy trucks, part of the Truck (T-series) program from the National Institute for Automotive Service Excellence. It certifies a technician's ability to diagnose and repair heavy-truck steering, suspension, alignment, and wheel/tire systems.
Bump steer: An unwanted change in toe (the wheels steer themselves) when the suspension moves over a bump, caused by worn parts or incorrect ride height altering the tie-rod geometry.
Camber: The inward or outward tilt of the wheel viewed from the front. Positive camber leans the top of the tire outward. Excessive camber wears one edge of the tire; unequal camber causes a pull.
Caster: The forward or rearward tilt of the steering axis (kingpin) viewed from the side. Positive caster aids straight-line stability and steering return; unequal caster side-to-side causes a pull.
Cupping (scalloped wear): A series of dips around the tread caused by the tire bouncing — usually worn shocks, loose bearings, imbalance, or a bent rim.
Dog-tracking: When the rear axle does not follow directly behind the front because of a misaligned (non-square) axle, so the truck travels slightly crab-wise.
Drag link: The steering link that connects the pitman arm to the steering arm on the axle, transferring the gear's motion to the wheels.
Dual wheels: The paired rear tires on each side of a heavy axle. They must be matched in pressure and diameter, or the larger/harder tire overloads and wears unevenly.
Feathered wear: A saw-tooth tread edge you can feel by hand, caused by incorrect toe scrubbing the tire sideways as it rolls.
Frame (rail): The truck's structural backbone. Twisting, cracks, or loose fasteners (often from overloading) misalign the axles and suspension.
Height-control valve: The valve that senses ride height at the axle and adds or exhausts air from the air springs to hold the frame level as load changes.
Integral power steering: A power-steering design that combines the steering gear and the hydraulic assist in a single unit, the standard arrangement on most medium/heavy trucks.
Kingpin: The pin on a solid front axle about which the steering knuckle (and wheel) pivots. Worn kingpins cause free play, wander, and shimmy on trucks that use them.
Leaf spring: A stack of curved steel leaves that supports the axle and carries the load. Sag, broken leaves, or a broken center bolt change ride height and can let the axle shift.
Linkage-type power steering: A design that uses a separate hydraulic power cylinder mounted on the steering linkage to assist a conventional gear.
Memory steer: The truck wanting to keep turning the direction it was last steered, usually from a binding ball joint, kingpin, or steering shaft.
Pitman arm: The arm splined to the steering-gear sector shaft that converts the gear's rotation into the back-and-forth motion of the drag link.
Power-steering pump: The engine-driven pump that supplies pressurized fluid for steering assist. A weak pump, low fluid, or air in the system causes hard steering and noise.
Radial runout: Out-of-roundness of a tire/wheel assembly that causes a speed-related vibration; corrected by truing, indexing, or replacement.
Recirculating-ball steering gear: The common heavy-truck steering gear in which balls circulate between the worm shaft and a ball nut to reduce friction and multiply the driver's effort.
Ride height: The specified distance from a reference point on the frame/axle to the ground. Correct ride height must be set before alignment, or the angles read wrong.
Shock absorber: A hydraulic damper that controls spring or air-bag oscillation. Worn shocks let the truck keep bouncing, causing tire cupping and poor control.
Spring center bolt: The bolt that locates the leaf-spring stack on the axle. If it breaks, the axle can shift, throwing off thrust angle and causing a pull.
Steering axis inclination (SAI): The inward tilt of the kingpin/steering axis viewed from the front. With camber it sets the scrub radius and helps the wheels self-center. SAI is a diagnostic angle — it is not adjustable, so a change indicates a bent part.
Steering free play (lash): The amount the steering wheel turns before the front wheels begin to move. Excessive free play comes from worn linkage, a worn gear, or loose bearings, and causes wander.
Technician A / Technician B: The signature ASE question format presenting two statements; you decide whether A only, B only, both, or neither is correct.
Thrust angle: The direction the rear (or tandem) axle actually points relative to the frame centerline. A non-zero thrust angle causes dog-tracking, an off-center steering wheel, and tire wear.
Tie rod: The link (with adjustable ends) that connects the two steered wheels so they turn together; the tie-rod sleeve is where toe is adjusted.
Toe: The difference between the front and rear of a pair of tires viewed from above (toe-in or toe-out). Incorrect toe is the leading cause of rapid, feathered front-tire wear; it is usually the only routinely adjusted front angle on a solid axle.
Turning radius (toe-out on turns): The geometry (Ackermann) that makes the inner wheel turn sharper than the outer through a corner. Built into the steering-arm angle; an error means a bent steering arm.
Walking-beam suspension: A tandem-axle design where a rigid equalizing beam pivots on a center saddle to share the load between the two axles over uneven ground; common on heavy vocational trucks.
Wheel balance: Distributing weight evenly around a tire/wheel assembly so it does not vibrate at speed; imbalance causes a shimmy that worsens with speed.
Wheel bearing: The tapered roller bearing that supports the wheel on the spindle. It is packed and adjusted to a small end play; over-tight bearings run hot and fail.

Free ASE T5 Study Materials & Resources

Everything you need to prepare for the ASE T5 test is free here — no paywall, no sign-up. This guide is the foundation; pair it with the rest of our free T5 study materials for active recall, timed practice, and last-minute review:

ASE T5 Practice Test — exam-style questions across all four content areas, with explanations.
ASE T5 Flashcards — active-recall decks for the components, procedures, and specs you must know cold.

ASE T5 Study Guide FAQ

The ASE T5 Suspension & Steering test has 70 multiple-choice questions and 1 hour and 15 minutes of testing time. Of the 70, 60 are scored and 10 are unscored research questions ASE is trying out for future tests; they are not identified, so answer every question.

References

1.ASE (National Institute for Automotive Service Excellence). “T5 Suspension & Steering Certification Test.” ASE. ↑
2.ASE. “Medium/Heavy Truck Certification Tests (T-Series).” ASE. ↑
3.ASE. “Dates, Fees & Test Times.” ASE. ↑
4.ASE. “myASE Account & Test Registration.” ASE. ↑
5.Federal Motor Carrier Safety Administration. “Inspection, Repair & Maintenance — Parts & Accessories (49 CFR 393).” U.S. DOT (FMCSA). ↑

Sources for the concept answers

Every answer in the ASE T5 concept questions above is drawn from an authoritative primary source:

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