Transport Trailer Technician Study Guide — Year 1

Year 1 Exam Topics

Study each topic below — these are the core knowledge areas tested in Year 1. Build a solid foundation here before advancing to Year 2 material.

📖Trailer Types

Dry van (box trailer): most common; enclosed box for dry freight; swing or roll-up rear doors
Flatbed: no sides/roof; carries oversized, construction, and steel loads; stake pockets for stakes
Reefer (refrigerated van): temperature-controlled cargo; diesel or electric refrigeration unit
Tanker: liquid or dry bulk; baffled or non-baffled; DOT rated for hazardous materials
Lowboy (low-bed): low deck height for oversized equipment; detachable gooseneck options
B-train: two trailers connected; second trailer on 5th wheel on rear of first trailer

📖5th Wheel & Coupling

5th wheel: horizontal plate with jaw that locks onto kingpin of semi-trailer
Kingpin: 50.8 mm (2") or 90 mm (3.5") standard; locking jaw must fully close around it
Coupling check: tug test — pull forward with trailer brakes off to verify latch is secure
5th wheel inspection: check jaw wear, lube, slide lock (for adjustable 5th wheels)

📖Air Brake System — Trailer

Supply line (red glad hand): charges trailer air tank from tractor; shuts off on breakaway
Service line (blue glad hand): carries brake application signal from tractor foot valve
Spring brakes: applied by spring force; released by air pressure (30–45 psi threshold)
Trailer brake valve (hand valve): applies trailer brakes only; used on grades to prevent jackknife

📖Landing Gear

High gear: fast crank for initial lowering when unloaded or lightly loaded
Low gear: slow crank with more torque for raising/lowering under heavy loads
Inspection: check for bent or cracked legs, worn crank handle, worn gear teeth
Never stand directly in front of landing gear legs — they can buckle under heavy load

📖Trailer Lighting (CCMTA)

Clearance lights: amber front, red rear — required on trailers over 2.03 m wide
Side marker lights: amber front half, red rear half of trailer
Stop/tail/turn: combined or separate rear lamps; must activate with brake application
Retroreflective tape: red/white alternating on sides; red on rear — required on trailers

🏗️Structural Inspection Points

Main frame rails: check for cracks, bends, corrosion — never weld without engineer approval
Crossmembers: support floor and distribute load to frame rails; check for corrosion and cracks
Kingpin plate: inspect for cracks radiating from kingpin; wear gauge required every 6 months
Tandem slider: check lock pins, track condition, and air lines when equipped

Study each topic below — these are the core knowledge areas tested in Year 1. Build a solid foundation here before advancing to Year 2 material.

📖ABS — Anti-Lock Braking

Trailer ABS: wheel speed sensors + ECU + modulator valve — prevents wheel lock-up
ABS lamp: yellow; illuminates on power-up and should extinguish after self-test
Diagnostic: flashing codes through ABS lamp or via J1587/J1939 diagnostic port
FMVSS 121: mandates ABS on all trailers with air brakes manufactured after March 1998

📖Reefer Unit Maintenance

Refrigerant: R-404A most common in transport reefers (phasing out — R-452A replacing)
Condenser coils: clean annually minimum; blocked coils reduce capacity and increase fuel use
Door seals: critical — compromised seals allow warm air infiltration; check weekly
Fuel system: reefer has its own diesel tank and engine — separate from tractor fuel

📖Tandem Slider Operation

Sliding tandem: moves axle group forward or rearward to adjust weight distribution
Bridge law: governs axle spacing to distribute weight and protect roads and bridges
Air release: most sliders use air-controlled pins; pins must fully engage before travel
King pin to rear axle: measured for bridge formula compliance; varies by province

📋FMVSS Standards — Trailers

FMVSS 108: lighting; FMVSS 121: air brakes; FMVSS 223/224: rear impact guards
Rear impact guard (ICC bumper): required on trailers over 4,536 kg GVWR; 560 mm from ground
Side underride protection: required on certain trailers in Canada (Transport Canada regs)
In Canada: federal regulations under Motor Vehicle Safety Act (MVSA) apply to new trailers

📖Air Brake Testing — Advanced

Static test: build to governor cut-out (~120 psi), shut off engine, loss must be <4 psi/min
Service brake test: 90 psi application, hold 1 minute — must not drop more than 6 psi
Spring brake test: drain service air; springs must fully apply — cannot release without air
Automatic brake adjuster: check stroke daily; 2" max stroke on 16.5" brake chamber

🔥Welding & Frame Repair

Frame rail repair requires engineer-approved procedure — never improvise repairs
Crossmember replacement: match OEM material spec; use proper fitment and stitch weld pattern
Kingpin replacement: press-fit kingpins require proper tooling and torque — no hammer installation
Floor replacement: match board species (oak or apitong); secure with proper screws into crossmembers