| A. General |
| MHT4A001 |
Research vehicle service information, including fluid type, vehicle service history, service precautions, and technical service bulletins. |
| MHT4A002 |
Disable and enable supplemental restraint system (SRS); verify indicator lamp operation. |
| MHT4A003 |
Identify suspension and steering system components and configurations. |
| MHT4A004 |
Use appropriate electronic service tool(s) and procedures to diagnose problems; check, record, and clear diagnostic codes; interpret digital multimeter (DMM) readings. |
| B. Steering Column |
| MHT4B001 |
Check steering wheel for free play, binding, and proper centering; inspect and service steering shaft U-joint(s), slip joint(s), bearings, bushings, and seals; phase steering shaft. |
| MHT4B002 |
Diagnose causes of fixed and driver adjustable steering column and shaft noise, looseness, and binding problems. |
| MHT4B003 |
Check cab mounting and adjust cab ride height. |
| MHT4B004 |
Remove the steering wheel (includes steering wheels equipped with electrical/electronic controls and components); install and center the steering wheel. |
| MHT4B005 |
Inspect, test, replace, and calibrate steering angle sensor. |
| C. Steering Pump and Gear Units |
| MHT4C001 |
Check power steering pump and gear operation, mountings, lines, and hoses; check fluid level and condition; service filter; inspect system for leaks. |
| MHT4C002 |
Flush and refill power steering system; purge air from system. |
| MHT4C003 |
Diagnose causes of power steering system noise, binding, darting/oversteer, reduced wheel cut, steering wheel kick, pulling, non-recovery, turning effort, looseness, hard steering, overheating, fluid leakage, and fluid aeration problems. |
| MHT4C004 |
Inspect, service, and/or replace power steering reservoir, seals, and gaskets. |
| MHT4C005 |
Inspect and/or replace power steering system cooler, lines, hoses, clamps, mountings, and fittings. |
| MHT4C006 |
Inspect and/or replace power steering gear(s) (single and/or dual) and mountings. |
| D. Steering Linkage |
| MHT4D001 |
Inspect, service, repair, and/or replace tie rod ends, ball joints, kingpins, pitman arms, idler arms, and other steering linkage components. |
| E. Suspension Systems |
| MHT4E001 |
Inspect, service, repair, and/or replace shock absorbers, bushings, brackets, and mounts. |
| MHT4E002 |
Inspect, repair, and/or replace leaf springs, center bolts, clips, pins, bushings, shackles, U-bolts, insulators, brackets, and mounts. |
| MHT4E003 |
Inspect, repair, and/or replace axle and axle aligning devices such as: radius rods, track bars, stabilizer bars, and torque arms; inspect related bushings, mounts, shims and attaching hardware; determine needed action. |
| MHT4E004 |
Inspect, repair, and/or replace tandem suspension equalizer components; determine needed action. |
| MHT4E005 |
Inspect, repair, and/or replace air springs, mounting plates, springs, suspension arms, and bushings. |
| MHT4E006 |
Inspect, test, repair, and/or replace air suspension pressure regulator and height control valves, lines, hoses, dump valves, and fittings; check and record ride height. |
| MHT4E007 |
Inspect and service kingpins, steering knuckle bushings, locks, bearings, seals, and covers. |
| MHT4E008 |
Measure, record and adjust ride height; determine needed action. |
| MHT4E009 |
Diagnose rough ride problems; determine needed action. |
| F. Wheel Alignment Diagnosis and Repair |
| MHT4F001 |
Demonstrate understanding of alignment angles. |
| MHT4F002 |
Diagnose causes of vehicle wandering, pulling, shimmy, hard steering, and off-center steering wheel problems. |
| MHT4F003 |
Check, record, and adjust camber. |
| MHT4F004 |
Check, record, and adjust caster. |
| MHT4F005 |
Check, record, and adjust toe settings. |
| MHT4F006 |
Check rear axle(s) alignment (thrustline/centerline) and tracking. |
| MHT4F007 |
Identify turning/Ackerman angle (toe-out-on-turns) problems. |
| MHT4F008 |
Check front axle alignment (centerline). |
| G. Wheels and Tires |
| MHT4G001 |
Inspect tire condition; identify tire wear patterns; measure tread depth; verify tire matching (diameter and tread); inspect valve stem and cap; set tire pressure; determine needed action. |
| MHT4G002 |
Diagnose wheel/tire vibration, shimmy, pounding, and hop (tramp) problems; determine needed action. |
| MHT4G003 |
Check wheel mounting hardware; check wheel condition; remove and install wheel/tire assemblies (steering and drive axle); torque fasteners to manufacturer’s specification using torque wrench. |
| MHT4G004 |
Inspect tire and wheel for proper application (size, load range, position, and tread design); determine needed action. |
| H. Frame and Coupling Devices |
| MHT4H001 |
Inspect, service, and/or adjust fifth wheel, pivot pins, bushings, locking mechanisms, mounting hardware, air lines, and fittings. |
| MHT4H002 |
Inspect frame and frame members for cracks, breaks, corrosion, distortion, elongated holes, looseness, and damage; determine needed action. |
| MHT4H003 |
Inspect, install, and/or replace frame hangers, brackets, and cross members; determine needed action. |
| MHT4H004 |
Inspect, repair, or replace pintle hooks and draw bars (if applicable). |
| MHT4H005 |
Inspect, service, and/or adjust sliding fifth wheel, tracks, stops, locking systems, air cylinders, springs, lines, hoses, and controls. |