mos.directory

Marine Corps MOS · Logistics

3521 Automotive Maintenance Technician

Current service use not established

This code is listed in the directory. Inclusion alone does not confirm current service use.

Browse Marine Corps

Overview

An Automotive Maintenance Technician services and inspects motor transport equipment at the field level. The technician also maintains and repairs this equipment.

Minimum ASVAB: EL 100 or MM 100

ASVAB policy: Not policy-reviewed · coverage unknown · as of 2026-10-19

Program scope has not been reviewed.

Policy applicability and coverage of the program's score routes have not been reviewed. Shown-route arithmetic is not an eligibility decision.

Source: navmc-1200-1l-fy26 (source date 2025-03). Policy applicability has not been established.

See if you would hit this score: free ASVAB practice test

Core Skills

  • Field-level motor transport equipment repair

Civilian Career Paths

Career associations are editorial assessments of the cited evidence, not an official crosswalk unless the evidence explicitly says so. O*NET supplies civilian occupation information, not proof of a military match. Related experience does not confer civilian qualifications. Tasks and tools below describe civilian work, not military training.

Automotive Service Technicians and Mechanics

Field-level servicing, inspection, maintenance, and repair of motor transport equipment transfer directly to civilian vehicle service work.

How to prepare: Take a hands-on course in civilian vehicle diagnostics that includes testing components and checking repairs against manufacturer specifications.

What the civilian work involves
  • Inspect vehicles for damage and record findings so that necessary repairs can be made.
  • Test drive vehicles and test components and systems, using equipment such as infrared engine analyzers, compression gauges, and computerized diagnostic devices.
  • Test and adjust repaired systems to meet manufacturers' performance specifications.

Bus and Truck Mechanics and Diesel Engine Specialists

Military motor transport equipment inspection, servicing, and repair provide a relevant foundation for bus and truck maintenance.

How to prepare: Complete hands-on diesel diagnostic training using test instruments and civilian engine diagnostic software such as Cummins INSITE.

What the civilian work involves
  • Inspect brake systems, steering mechanisms, wheel bearings, and other important parts to ensure that they are in proper operating condition.
  • Adjust and reline brakes, align wheels, tighten bolts and screws, and reassemble equipment.
  • Attach test instruments to equipment, and read dials and gauges to diagnose malfunctions.
Civilian tools and software (examples)
  • Computerized maintenance management system software CMMS
  • Cummins INSITE

Notes & Sources

Evidence for this guidance (3 documents)
  1. NAVMC 1200.1L (FY26, in force): MOS 3521

    [1] MOS 3521 section "a. Summary"; cached text line 44023; NAVMC 1200.1L signed 2025-03-07, in force until 2026-10-01

    Supports: Field-level motor transport equipment repair, Automotive Service Technicians and Mechanics (O*NET 49-3023.00), Bus and Truck Mechanics and Diesel Engine Specialists (O*NET 49-3031.00)

    [2]NAVMC 1200.1L MOS 3521: Related SOC titles · MOS 3521 section "e. Related Standard Occupational Classification"

    Supports: Automotive Service Technicians and Mechanics (O*NET 49-3023.00)

  2. O*NET: Automotive Service Technicians and Mechanics

    [3] O*NET 30.3 occupational data

    Supports: Automotive Service Technicians and Mechanics (O*NET 49-3023.00)

  3. O*NET: Bus and Truck Mechanics and Diesel Engine Specialists

    [4] O*NET 30.3 occupational data

    Supports: Bus and Truck Mechanics and Diesel Engine Specialists (O*NET 49-3031.00)

Defense contractor jobs for 3521

Descriptions may be summarized for clarity. Verify all information with your branch career counselor or official military documentation before making career decisions.

Report an error on this page