The 6.7 Cummins is a strong engine, but emissions tampering, front-end wobble, and exhaust leaks are the real story. Tuned trucks need extra caution.
The Cummins is one of the most respected diesels on the road, and the engine itself rarely lets you down. The risk in buying one is everything around it — emissions systems that owners often delete (a legal and resale problem), the front end, and the things that break on a truck that's been worked hard.
Many trucks have illegal EGR/DPF deletes and tunes that create legal, registration, and resale problems.
CHECK Scan the ECM, verify emissions hardware, and confirm regen on stock trucks.
Solid-axle Rams are prone to a steering oscillation from worn track bar and links.
CHECK Inspect the track bar and steering and road test over rough pavement.
Manifold bolts loosen or break, causing a tick and exhaust leak.
CHECK Listen for a cold-start exhaust tick that fades as the engine warms.
The variable-geometry turbo actuator can stick and trigger limp mode.
CHECK Scan for turbo codes and road test for lack of power or limp mode.
The automatic struggles behind heavy tuning and hard towing.
CHECK Check fluid condition and road test for slip or harsh shifts.
Bidirectional OBD-II scan tool · Paint depth gauge · Tire tread depth gauge & DOT date decoder · Brake pad & rotor calipers / measurement tools · Battery & charging system tester · Compression and cylinder leak-down testers · Digital borescope · Floor jack and jack stands …
See the full Pre-Purchase Vehicle Inspection tool kit →
Pre-tagged for the Ram 2500 / 3500 Cummins (2007.5–2018).