Engine & Transmission Experts in Lakeland, FL
Whether you drive a diesel pusher with a Cummins ISL or a Class C with a Ford V10, your engine and transmission are the most critical systems on your RV or bus. A misfire, a transmission slip, or an unexplained loss of power can turn a vacation into a breakdown and a fleet schedule into a logistics nightmare. At Nationwide Haul in Lakeland, FL, we service all major gas and diesel platforms with the expertise and precision these powertrains demand.
Our shop is equipped with 2026 diagnostic technology and staffed by ASE Master Certified technicians who specialize in heavy-duty RV and bus powertrain systems. Factory-level scan tools read every module on your vehicle—ECM, TCM, ABS, body controller—so we pinpoint the real problem, not just guess. That means faster turnarounds, fewer comebacks, and repairs that address the root cause instead of chasing symptoms.
From a routine transmission fluid service to a complete in-frame engine overhaul, we handle every level of powertrain work in-house. No subcontracting, no shuttling your rig between shops. One team, one facility, one point of accountability for the most important systems on your vehicle.
Engine & Transmission Services We Provide
Diesel Engine Service
Diesel engines power the majority of Class A motorhomes and commercial buses on the road today, and each platform has its own architecture, fault codes, and service requirements. Our technicians are experienced across Cummins (ISB 6.7, ISL 8.9, ISX 15, B6.7, L9, X15), Caterpillar (C7, C9, C13), Detroit Diesel (DD13, DD15), and International/Navistar engines. We perform complete diagnostics, fuel system service including injector testing and high-pressure fuel pump evaluation, turbocharger inspection and replacement, cooling system repair, and exhaust aftertreatment service covering DPF, DEF, and SCR systems. Whether it is an oil leak at the rear main seal, a blown head gasket, or a turbo that is not building boost, we have the tooling and training to diagnose it accurately and repair it right.
Gas Engine Service
Gas-powered RVs and shuttle buses are workhorses in their own right, and the engines that drive them require specialized attention beyond what a typical automotive shop can provide. We service the Ford V10 6.8L found in thousands of Class C motorhomes and E-Series bus chassis, the Ford 7.3L Godzilla V8 in newer Super Duty-based platforms, Chevy Vortec 6.0 and 8.1 engines common in Workhorse and P-Series chassis, and Mercedes OM642/OM654 turbodiesels in Sprinter-based Class C and B+ coaches. Our gas engine services include fuel injection diagnostics, ignition system repair, exhaust and emissions service, cooling system overhaul, and complete drivability diagnostics for issues like misfires, rough idle, and poor fuel economy.
Transmission Service
Your transmission absorbs enormous stress—especially when pulling grades in a 30,000-pound motorhome or running stop-and-go routes in a transit bus. We service all major automatic transmission platforms including Allison (1000, 2000, 3000, and B500 series), Ford (6R140, 10R140, TorqShift), and Mercedes 7G-Tronic. Our transmission services include fluid and filter service using OEM-spec fluids, valve body diagnostics and repair, solenoid pack replacement, torque converter evaluation and replacement, and complete transmission rebuilds when needed. We also perform transmission adaptation resets and TCM reprogramming after service to ensure smooth, factory-quality shift behavior.
Engine Overhauls
When an engine has high miles, low compression, or excessive oil consumption, a full overhaul can restore its power and reliability at a fraction of the cost of a complete replacement. We perform both in-frame and out-of-frame overhauls depending on the engine platform and the extent of wear. In-frame overhauls address pistons, liners, rings, bearings, and gaskets without removing the engine from the chassis—reducing labor time and cost. Out-of-frame overhauls allow for complete disassembly, block inspection, crankshaft measurement, and camshaft evaluation for engines that need deeper restoration. Every overhaul includes new seals, fresh fluids, and a comprehensive post-rebuild test to verify compression, oil pressure, and overall performance before your rig leaves the shop.
Cooling System
Overheating is one of the fastest ways to destroy a diesel or gas engine, and RVs and buses are especially vulnerable because of the heat loads generated during sustained highway driving and mountain grades. We service every component in the cooling circuit including radiators, water pumps, thermostats, hoses, heater cores, and charge air coolers (CAC). Our coolant flush and fill service uses the correct OEM-specified coolant—OAT, ELC, or conventional—matched to your engine platform. We also test for combustion gas intrusion, which can indicate a head gasket failure, and perform pressure tests to locate slow leaks before they become catastrophic failures on the road.
Exhaust & Aftertreatment
Modern diesel engines rely on complex aftertreatment systems to meet emissions standards, and when these systems malfunction, the consequences range from reduced power to complete engine derate. We provide DPF cleaning and replacement, DEF system diagnostics including dosing valve and quality sensor testing, SCR catalyst evaluation, EGR valve service, and turbo actuator repair. When your engine is stuck in a derate condition or requesting a forced regeneration, our technicians use factory-level software to perform forced regens, clear stored fault codes, and verify that the aftertreatment system is operating within specification. We also diagnose and repair exhaust leaks, flex pipes, and clamp failures that can cause nuisance codes and failed inspections.
Engine Platforms We Service
Our technicians work across the full spectrum of RV and bus engine platforms. Here is a breakdown by vehicle type:
Class A Diesel Pushers
Cummins ISL 8.9 and ISB 6.7 are the dominant platforms in modern diesel pushers from Tiffin, Newmar, Entegra, and Thor. Older coaches may run Caterpillar C7 or C9 engines. Transmissions are typically Allison 3000 series. We service all model years and configurations.
Class C & Gas Motorhomes
The Ford V10 6.8L is the backbone of the Class C segment, powering coaches from Thor, Coachmen, Winnebago, and Forest River. Newer models feature the Ford 7.3L Godzilla or the Chevy 6.0 Vortec. Sprinter-based Class C and B+ coaches use the Mercedes OM642 3.0L V6 turbodiesel or the newer OM654 2.0L inline-4 turbodiesel. Transmissions include the Ford TorqShift 6R140, 10R140, and Mercedes 7G-Tronic.
Buses & Commercial Coaches
School buses, transit buses, shuttle buses, and church buses commonly run Cummins B6.7 and ISB 6.7, International A26, and Detroit Diesel DD13 and DD15 engines paired with Allison 2000 and 3000 series transmissions. We service all commercial bus platforms including Blue Bird, Thomas Built, IC Bus, and Prevost coaches.
Signs Your Engine or Transmission Needs Service
Catching powertrain problems early almost always saves money and prevents roadside breakdowns. Schedule a diagnostic appointment if you notice any of the following:
- Check Engine Light — the most common indicator. Even if the vehicle seems to run fine, a stored fault code can point to a developing issue before it becomes a failure
- Loss of Power — if your RV or bus struggles on hills it used to climb easily, the engine or turbo system may need attention
- Rough Idle — a diesel that shakes excessively at idle or a gas engine that hunts for RPM can indicate injector, compression, or ignition problems
- Excessive Smoke — black smoke points to fueling issues, white smoke to coolant intrusion or low compression, and blue smoke to oil consumption
- Unusual Noise — knocking, ticking, whining, or grinding sounds from the engine or transmission bay warrant immediate inspection
- Transmission Slipping — if RPMs flare without a corresponding increase in speed, the transmission is not transferring power efficiently
- Hard or Delayed Shifting — harsh shifts, delayed engagement, or a transmission that hangs in gear too long can indicate valve body, solenoid, or fluid issues
- Overheating — a rising temperature gauge or a low coolant warning demands immediate attention to prevent catastrophic engine damage
- Coolant Loss — if you are adding coolant regularly without a visible external leak, an internal leak at the head gasket or EGR cooler is possible
Why Choose Nationwide Haul
- Factory-Level Diagnostics — scan tools that communicate with every module on your vehicle, not just the engine. We see the complete picture before we recommend any work
- All-Platform Expertise — Cummins, Caterpillar, Detroit, Ford, Chevy, Mercedes, Allison. Diesel and gas. RVs and buses. One shop that handles it all
- ASE Master Certified Technicians — our team holds advanced certifications in diesel engine repair, automatic transmission service, and electronic systems diagnostics
- Warranty-Friendly Service — we work with extended warranties and RV protection plans including Good Sam, Wholesale Warranties, and coach manufacturer programs. Hassle-free claims processing
- Honest, Transparent Estimates — detailed repair quotes before any work begins. No surprises on your invoice. We explain what we found, what we recommend, and why
- In-House Overhaul Capability — from routine maintenance to complete engine and transmission rebuilds, everything is performed in our Lakeland facility by our own technicians