6.7 Cummins Repair, Gen 3 Through Gen 5
6.7 Cummins repair starts with the model year, because the engine that went into Dodge Ram heavy-duty trucks in mid-2007 has changed pumps, emissions hardware and transmissions since. We confirm which version you have, then find the system that is actually failing.
Same inline six, three generations of truck around it
The 6.7 kept what owners liked about the 5.9: six cylinders in a row and a cast iron block. What changed was everything bolted to it: a Holset variable geometry turbo, EGR and a DPF from day one, then SCR and DEF on 2013 and newer pickups.
If your Ram has the older 5.9 (1994 to early 2007), see our 5.9 Cummins repair.
| Spec | CP3 | CP4 |
|---|---|---|
| Model years | 2007.5 to 2018 | 2019 and 2020 |
| Fuel tolerance | More forgiving of poor fuel | Water, air and low lubricity wear it |
| How it tends to fail | Low pressure, hard starts, low power | Can fail fast and send metal to the injectors |
We do not do delete work. Emissions parts get repaired and stay on.
A 6.7 job too big for the home garage
Owners who work on their own trucks still bring us the long teardown jobs.
319 reviews
- Customer
- MDC
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- 2016 Ram 3500 6.7
I like to work on my own vehicles but I took my 2016 Ram 3500 6.7 to have the front timing case seal done which is a very large job and beyond my expertise. The owner is very knowledgeable and I appreciate his direct advice. They did an excellent job and went above and beyond to make sure my truck was done correctly. I wouldn’t hesitate to use them again.5 STARS
What your 6.7 carries, by model year
Pick your truck's years to see the hardware it runs.
Gen 3: the first 6.7 trucks
CP3 pump, Holset VGT, EGR, a DPF and a NOx adsorber instead of DEF, with the 68RFE six-speed on most pickups. At this age soot is the common thread: it sticks turbo vanes and loads the EGR cooler and filter.
Unfinished regens, turbo vanes, EGR cooler leaks and front end wear.
Early Gen 4: new truck, same exhaust recipe
Ram redesigned the truck for 2010, but the engine side stayed close to Gen 3, and pickups still had no DEF tank. Trucks that idle a lot or only make short trips pay for it in regens.
Soot load, a sticking EGR valve, VGT codes and 68RFE fluid.
2013 to 2018: SCR and DEF arrive
Pickups add SCR and DEF: a tank, pump, heaters, doser and NOx sensors. The CP3 stays. High-output 3500 and cab-chassis trucks use an Aisin six-speed; most others keep the 68RFE. DEF faults now end in a countdown to reduced speed.
DEF quality, heaters, NOx sensors and which transmission it has.
Gen 5: 2019 to 2024
On 2019 and 2020 trucks the 6.7 runs a CP4. It does the job on clean fuel, but water, air and poor fuel wear it, and a worn CP4 can shed metal into the injectors. Filter changes and draining the water separator matter more here than on any earlier 6.7.
Water in the separator, glitter in the filter and rail pressure.
2025 and newer: a new transmission
Standard-output trucks move to a ZF eight-speed. The engine side carries over: CP4, Holset VGT, EGR, DPF and SCR with DEF. Shift complaints start with a scan and fluid check.
Shift codes, fuel filters and regen history.
Six systems that bring a 6.7 through our door
Each links to its full repair page.
CP3 and CP4 pumps
Low rail pressure, hard starts and failed pumps, plus where any metal went. See diesel injection pump repair.
Fuel supply and injectors
Water, air, contamination and injectors that leak or stick. See diesel fuel system repair.
EGR cooler and valve
Internal coolant leaks, plugged coolers and stuck valves. See EGR cooler replacement.
DEF and SCR
Heaters, pumps, dosers and NOx sensors on 2013 and newer pickups. See DEF system repair.
Grades, cold mornings and short hops
Many 6.7 owners here tow campers up long mountain grades and hold them back coming down. That is heat for the transmission and cooling system, and at elevation a VGT that is starting to stick shows up sooner.
In winter the grid heater and batteries carry cold starts, and DEF freezes near 12 degrees Fahrenheit, so a weak DEF heater shows itself on the first cold snap.
- Towing a grade: watch both temperature gauges
- Below freezing: grid heater and DEF heaters
- Short trips only: add a highway run for regens
Ease off, pull over where it is safe and let it idle. If it keeps climbing, shut it down and call us.
What the truck is doing, and where that usually leads
A starting point, not a diagnosis.
| What you notice | What it often is on a 6.7 | First thing we check |
|---|---|---|
| Hard start, stalls under load, rail pressure codes | Fuel supply, filters or the high-pressure pump | Filters for water and metal, then rail pressure |
| Low power, surging boost, turbo whistle | VGT vanes sticking from soot, or a boost leak | Vane movement and charge pipes |
| Coolant dropping, no puddle | An EGR cooler leaking inside | A cooling system pressure test |
| Constant regens, filter messages | A DPF loading from extra soot upstream | Soot load, then injectors, EGR and turbo |
| DEF warning or a speed limit countdown | DEF quality, a heater, pump or NOx sensor | DEF quality and both NOx sensor readings |
| Flashing overdrive or tow/haul light, slipping | Transmission heat or internal wear | Codes and fluid, then diesel transmission repair if needed |
Not listed? Our diesel diagnostics start from what the truck is doing.
What moves the price of a 6.7 repair
- Model year and the hardware it carries
- How far a failure spread, like pump metal
- How much teardown the job takes, such as a front timing case seal
- New or remanufactured parts, where both are offered
- Work in the same area, done together
One symptom can be a filter or a whole fuel system, so we price a 6.7 once we know what failed.
How we handle 6.7 Cummins repair, start to finish
The same steps on every 6.7, whatever the year.
Model year first
The VIN and build data tell us the pump, emissions setup and transmission.
Test the system
OEM factory scan tools, then pressure, boost, soot or DEF tests.
Follow the damage
Pump metal, soot or coolant: we check what the failure reached.
Call before work
Now versus later, and where labor overlaps. Nothing starts without your approval.
Tell us what your 6.7 Cummins is doing
Send the year, the engine and what you are seeing, and we'll get back to you as quickly as we can.
- Year, make and engine
- What it is doing, and when it started
- Any codes or recent repairs
Rather talk it through? Call (303) 808-1563
6.7 Cummins questions we hear at the counter
What owners ask before dropping a truck off.
Trucks through 2018 use the CP3; 2019 and 2020 trucks use the CP4, which is less forgiving of water and poor fuel. Every 6.7 Cummins repair here starts by confirming which pump is on the truck.
Short trips and idling keep regens from finishing. Otherwise an injector, the EGR or a sticking turbo is usually making extra soot, and we find that source.
Most 2007.5 to 2024 trucks use the 68RFE six-speed. High-output 3500 and cab-chassis trucks use an Aisin, and 2025 and newer standard-output trucks a ZF eight-speed.
No. We do not do delete work. Our 6.7 Cummins repair means the EGR, DPF and the NOx adsorber or SCR system get fixed and stay on the truck.
Diagnosis typically takes 24 to 72 hours depending on workload. Repair time depends on what we find and on parts.
Is your 6.7 regenning, smoking or counting down?
Call with the model year and what changed, or use Request Service to send the details. Or drop us a line right here from the website and we'll get back to you as quickly as we can.