Medium-Duty Fleet Maintenance (Class 5–7)

Medium-duty trucks are the fleet nobody plans for — the service bodies, stake beds, chip trucks, and crew trucks that support the real work and get maintained “when there’s time.” They still carry inspection obligations (many cross the 10,001-lb federal line; California’s BIT reaches three-axle trucks over 10,000 lbs, tractors, heavy combinations and 26,001-lb-plus units — since 2025, no longer every DMV-permitted truck), and they still strand crews when ignored.

What Class 5–7 fleets actually face

• Vocational duty in a smaller package — idle-heavy days, PTO loads, and upfit electrical systems that tax charging like accessories always do
• Inspection ambiguity — which units are BIT-covered, which need federal annuals; we sort each unit’s actual obligations at the assessment rather than guessing fleet-wide
• Mixed-badge reality — an International MV next to a Freightliner M2 next to a Hino; one shop covering all ten confirmed brands beats three vendors covering three each
• Diesel aftertreatment in miniature — the same DPF/DEF systems as the big trucks, with duty cycles that fight them (see regen service)

Same bays as the Class 8s — on purpose

Medium-duties here get heavy-truck discipline: measured brake checks, real PM rhythms set from duty cycle, per-unit records, and on-site service where the trucks live. The boundary stays honest: consumer-class pickups belong at a light-duty shop — Class 5 and up is where we start.

Upfit electrical: where medium-duty faults start

Service bodies, cranes, compressors, inverters, beacon bars and chip-box hydraulics all tap the chassis electrical system, often through installer wiring that was never on the manufacturer’s drawing. Parasitic drains, overloaded grounds and chafed upfit harnesses are the usual causes of the intermittent faults that look like “the truck’s electrical system is bad.” Diagnosis here starts at the upfit, because that is where the truck was last changed.

Hydraulic brakes need different numbers

Many Class 5 and 6 trucks run hydraulic rather than air brakes, with disc pads and rotors in place of drums and chambers. The federal minimum pad thickness for hydraulic brakes is far thinner than for air drums, so a “looks fine” glance misses pads at the limit. PMs here record pad thickness and rotor condition per wheel, and check the hydraulic booster or ABS module for the codes those systems set quietly.

PTO hours, not miles

A chip truck or crane truck can run its engine all day and move ten miles. Oil life, cooling-system load and aftertreatment soot all track engine hours and idle percentage on these units, so intervals set from the odometer under-maintain them badly. The truck records hours and PTO time; the program is set from those.

Do our 3/4-ton pickups fit this program?

Below our line, honestly — we’re built from Class 5 up. We’ll happily maintain the medium and heavy units while your pickups see a light-duty shop.

Our medium-duties tow trailers — does that change compliance?

It can — combinations change BIT and inspection math. Bring the real configurations to the assessment and each unit gets its true obligations mapped.

Gas-engine medium-duties too?

Our depth is diesel; gas medium-duties are case-by-case — ask when you call and we’ll answer for your specific units rather than overclaim here.

Which of our medium-duties need the federal annual inspection?

Generally every unit over 10,000 lbs GVWR used in interstate commerce, including trailers that push a combination over the line. Intrastate-only operations follow California’s rules, which can differ. We map each unit’s obligations from its registration and configuration at the assessment rather than guessing.

Do you work on Isuzu and Hino cab-overs?

Yes — both are on our confirmed service list alongside International, Freightliner and the other medium-duty badges. The engine platform and model year drive the diagnostic path more than the badge does.