Newmar RV Motorhome Repair Service
Newmar coaches are built for comfort, safety, and long miles. We keep them that way with brand-aware diagnostics, spec-correct parts, and tight communication—covering both the coach and the chassis so you can travel with confidence.
Diagnostics & Common Repairs
We follow a test-first workflow to pinpoint faults before parts go on.
What we solve most often:
- Drivability & power: derates/regens, boost leaks, fuel delivery, cooling on grades.
- Electrical (12V/120V): charging, parasitic draws, multiplex/logic faults, bad grounds.
- HVAC & hydronic heat: roof A/C performance, Aqua-Hot/Hydro-Hot service, blower/zone control.
- Slide-outs & leveling: HWH/Lippert hydraulics, sensors, seals, ride-height & air-leak checks.
- Generator: Cummins/Onan hard starts, voltage and frequency stability, maintenance resets.
- Brakes/suspension/steering: air system leaks, dryers, valves, hubs, alignment, shocks.
- Plumbing & LP: pump/accumulator issues, water heater, tank sensors, fittings, winterization.
Chassis & Powertrains We Service
- Freightliner & Spartan chassis (and select other platforms).
- Cummins L9 / ISL / ISB (and applicable variants).
- Allison 3000/4000 transmissions—diagnostics, adaptations, fluid/filter service.
Engine, transmission, air system, and cooling work are coordinated in one plan with a road-test and datalog to confirm the fix.
Coach Systems & Upfits
- Inverter/charger systems (Magnum, Victron), battery upgrades and load tests.
- Roof, cap, and seam inspections; sealant renewal; awning service.
- Lighting, cameras, TPMS and safety electronics; step/door modules; appliance diagnosis.
Major Repairs — Engine
When a repair goes beyond routine PM, we scope the job around your travel plans and confirm failure before parts are ordered.
- Failure confirmation: compression/leak-down, injector balance/return, fuel pressure & restriction, boost & CAC integrity, cooling pressure/flow, oil analysis.
- In-frame/Out-of-frame overhauls: cylinder head service, liners/pistons, rings, bearings, oil pump, timing components, full gasket/seal kits, overhead set to spec.
- Air & fuel systems: turbo/VGT and actuator checks, charge-air piping and clamps, high-pressure fuel testing, rail/injector replacement as needed.
- Aftertreatment integration (where equipped): DPF cleaning/replacement, DOC/DEF system checks, NOx/temp sensor calibration, EGR diagnostics so post-overhaul regens and derates don’t return.
- Cooling system restoration: radiator/CAC replacement, water pump, thermostats, hoses, surge tank, fan hub/clutch control.
- Validation: hot/cold starts, no-load and on-grade road tests, leak/boost checks, and data logs. You leave with VIN/coach-level documentation and break-in recommendations.
Major Repairs — Transmission
Focused on Allison 3000/4000 (and applicable platforms) with attention to heat management and shift quality.
- Diagnostics first: TCM codes, adaptation status, clutch wear data (where available), line pressure tests, harness/ground checks, cooler flow and temperature trend review.
- Service & repair: fluid and filters to spec, external leaks and seals, range/NSBU switch, speed sensors, wiring and connectors, cooler and lines.
- Rebuilds & replacements: clutch packs, torque converter, valve body/solenoids, internal seals; or approved reman units when downtime or economics favor a swap.
- Calibrations & learn: resets/adaptations, shift quality tuning, PTO function checks (if equipped).
- Validation: temperature-controlled road test (starts, up/downshifts, lockup), no-drip recheck, and a printed report with next-service interval and fluid spec noted.
Both engine and transmission projects are planned with clear estimates, timelines, and parts options—so you know what’s required now and what can be scheduled later.
Preventive Maintenance & Trip-Readiness
- Chassis PM: engine oil/filters, fuel filtration, coolant testing/exchange, CAC/boost integrity, belts/hoses, Allison fluid/filter, axle & hub service, air dryer.
- Generator PM: oil, filters, spark (where applicable), mounts, output checks.
- Coach PM: battery health, slide/leveling lubrication & calibrations, roof/awning inspection, tank & freshwater sanitization, LP leak test.
You’ll leave with VIN/coach-level documentation and a clear next-service plan.
Newmar service done right—coach and chassis under one roof, documented, and road-tested.
Local Shop
Skilled Mechanics
Quality Equipment
Benefits of Service
Prevent unexpected breakdowns on your road trip. Test-first diagnostics, OEM-spec parts, and trip-ready inspections keep your coach and chassis reliable—so you spend more time exploring and less time on the shoulder.
- Newmar-expert diagnostics
- Fast turnarounds / Less downtime
- Quality OEM-spec parts
- Trip-ready inspection
- PM done right
Newmar RV Service FAQs
Get fast answers about Newmar RV service at Britt’s Diesel—coach + chassis coverage (Freightliner/Spartan), Cummins/Allison support, diagnostics for derates/power issues, PM before long trips, and engine/transmission major repairs.
We work on all Newmar coaches—King Aire, London Aire, Dutch Star, Ventana, Supreme Aire and more—on Freightliner and Spartan chassis with Cummins engines and Allison 3000/4000 transmissions. We also service Cummins/Onan generators.
We build one work order and schedule parallel tasks: a chassis bay handles engine/trans/brakes while a coach tech tackles slides, leveling, electrical, HVAC, and plumbing. Parts are pre-staged after diagnostics, then we finish with a single road test and leak/functional recheck so you’re not making multiple trips.
Absolutely. Engines: failure confirmation, in-frame/out-of-frame overhauls, turbo/charge-air, cooling, and aftertreatment integration. Transmissions: Allison diagnostics, service, rebuilds or reman swaps, calibrations/adaptives, and cooler flow checks. We provide clear estimates and timelines.
Chassis PM (oil/fuel filters, coolant testing, belts/hoses, CAC/boost integrity, axle/Allison fluids), generator PM, and coach PM (battery load tests, inverter settings, slide/leveling lube, roof/awning inspection, LP leak test, tank sanitization). Booking a couple of weeks ahead is ideal.
Yes—do a quick post-trip checklist within 24–48 hours:
Fluids & filters: Check engine oil, coolant, transmission fluid, DEF, and power steering; drain the fuel/water separator if equipped.
Tires & wheels: Set cold PSI, inspect tread/sidewalls, look for uneven wear; re-torque lugs (especially after service or long grades).
Air/brakes/suspension: Listen for air leaks, confirm dryer purges, check ride height and any brake pull or vibration notes from the trip.
Cooling & undercarriage: Rinse bugs/road grime from radiator/CAC, look for leaks or loose clamps/hoses.
Batteries & power: Verify house/chassis SOC, water levels (if serviceable), shore/inverter-charger settings; run the generator under load 30–60 min.
Coach systems: Inspect roof seams, slide seals/levelers (clean/lube), test GFCIs and LP detector; sanitize fresh water system seasonally.
Record & schedule: Log mileage/hours, any regen/derate events, and book PM (oil, fuel filters, coolant, Allison service) on time.
If storing >60 days: Add fuel stabilizer, top DEF, exercise monthly (drive or run to temp), and maintain TPMS.