1985 Autocar: we work on any truck
If it runs diesel and needs help, we'll show up. Age is not a barrier: classic, vintage, or modern.
Mobile Mack Repair
Mack Truck Repair in Charleston, SC. We Come to You.
Lowcountry Diagnostics is an independent mobile diesel shop, not a Mack dealer. We bring the scan tool and test equipment to your Anthem, Granite, Pinnacle, LR or MD wherever it is parked in the Charleston area, find the failed part through testing, and explain the result plainly.
- MP7 and MP8 derates, EGR cooler coolant loss, DPF and SCR faults
- mDRIVE shift complaints, air supply, electrical and no-start problems
- Charleston, North Charleston, Summerville, Goose Creek, Mount Pleasant
Common Mack Failures
What goes wrong on Macks and how we find it
EGR cooler coolant loss
Mack MP engines use cooled EGR, so exhaust gas runs through a cooler that shares the engine coolant. When that cooler cracks inside, the level drops with no drip on the ground, sometimes with white smoke or EGR and NOx codes. We pressure test the cooling system, check for combustion gas in the coolant, and inspect the EGR side before calling the cooler.
ClearTech DPF and SCR derates
Since 2010 Mack has paired EGR with SCR and DEF under the ClearTech name, and conventional models later moved to ClearTech One, a single box holding the DPF, SCR and DEF dosing. A soot-loaded filter, a NOx sensor reading out of range, or a doser that cannot deliver will cut power. We compare sensor readings, check DPF differential pressure, and run a dosing test. When the filter itself needs it, we handle DPF cleaning too.
mDRIVE shifting complaints
The mDRIVE is Mack's 12-speed automated manual, derived from the Volvo I-Shift and operated by air. Leaks, wet air from a neglected dryer, or a worn clutch actuator can cause missed gears, a truck that will not pull away, or clutch codes. We check supply pressure and the dryer first, then read the transmission codes.
Electrical faults and no-starts
Corroded grounds, chafed harnesses and tired batteries cause no-cranks, dead gauges and communication codes. We load test, voltage-drop the cables, and trace the data link before replacing a module.
Know Your Mack
Mack models, engines and transmissions
Mack Trucks has been part of the Volvo Group since 2001. That is why the MP8 and the Volvo 13-liter share their basic engine design, and why the mDRIVE traces back to the I-Shift. We also handle Volvo truck repair.
The Anthem is the highway tractor that took over from the axle-back Pinnacle in 2017, while the Pinnacle continues in its axle-forward form. The Granite is the vocational model for dump and mixer work, offered with the MP7 or MP8 behind an Eaton Fuller manual, the mDRIVE HD, or an Allison automatic.
The MP7 is an 11-liter engine and the MP8 is a 13-liter. The MP8HE adds turbo compounding, which captures exhaust energy and feeds it back to the crankshaft, and Mack has since released a newer version of the MP8HE that it rates at up to 3 percent better fuel efficiency.
The LR is a low-entry cab-over built for refuse routes, with the MP7 as its standard diesel. The MD6 and MD7 medium-duty trucks, introduced in 2020, run a Cummins B6.7 with an Allison automatic.
Why Mack owners call us
- Independent shop, not a dealer
- We test before we order parts
- Written findings after the job
- 13 years in the diesel trade
- Open 24/7 in the Charleston area
Before We Roll
What to text us about your Mack
1. Model, engine and year
Anthem, Granite, Pinnacle, LR or MD, plus the engine (MP7, MP8, MP8HE, or the Cummins B6.7 in an MD) and the year or VIN.
2. A photo of the codes
Snap the dash messages or fault code screen, including any derate warning.
3. What changed and when
Coolant you keep adding, recent repairs, unfinished regens, or shifting trouble. Note whether it happens loaded or empty.
4. Where the truck sits
Yard address, jobsite gate, or mile marker. All of our work happens on-site.
5. On-site testing
We pull live data and check NOx readings, DEF delivery, DPF pressure, boost, air supply, and battery and ground voltage.
6. Findings in writing
You get the tests we ran, what failed, and the repair we recommend.
Mack down in the Charleston area?
Text the model, engine and fault codes to (843) 310-0995 and we will head to the truck.
Mack repair questions
Are you a Mack dealer?
No. Lowcountry Diagnostics is an independent mobile diesel repair business. Joseph Cufaude, our founder and lead technician, has 13 years in the diesel trade, and all of our work is done on-site at your truck.
Do you work on Mack MP7 and MP8 engines?
Yes. We diagnose and repair MP7, MP8 and MP8HE engines, including EGR cooler coolant loss, NOx sensor and DEF dosing faults, and DPF related derates.
Can you diagnose mDRIVE shifting problems?
Yes. The mDRIVE is air operated, so we start by checking for air leaks and the condition of the air dryer, then read the transmission codes and test the clutch actuator.
Do you clean Mack DPFs?
Yes. We offer DPF cleaning, and we also look for the reason the filter loaded up, such as regens that never finish, an EGR problem, or a leaking EGR cooler.
Do you work on Mack refuse and medium-duty trucks?
Yes. We work on the diesel LR refuse truck and on the MD6 and MD7 with the Cummins B6.7, at your yard, transfer station, or jobsite.
Request Mack Truck Repair
Tell us where the Mack is, the model and engine, and what it is doing.
Mack down or in derate? Call or text (843) 310-0995 now.
Recent Repair Photos
A look at the repairs we make
Real field photos from Lowcountry Diagnostics, from engine diagnostics and electrical to hydraulic, HVAC, and heavy-duty truck service, handled on-site across the Charleston area.
Reviews
What Charleston truck owners and fleets say
“Great team, personal and professional. These men were responsive and had great diagnostic equipment paired with experience…”
“These guys really know their stuff. Couldn't recommend em more.”