Chasing Down Engine Noise on a 2020 Ram 3500 6.7 Cummins

Issue: The customer brought in their 2020 Ram 3500 6.7 Cummins , concerned about a loud ticking noise. While most noticeable at idle, the noise was present at higher RPMs as well. The noise had a slow, rhythmic beat and seemed to be coming from somewhere near the turbo area.

Initial Diagnostics

The check engine light was off. Scanning for DTCs revealed no stored or active codes in any module. Continuing diagnostics, I took the Cummins out for a test drive to monitor noise conditions.

The ticking was present both at idle and under load. As the RPM climbed, the rhythm of the noise matched it exactly—clear evidence that this was tied to engine speed.

Back in the shop, with the truck up on the lift and the engine steady at 2,000 RPM, I used a stethoscope to track it down. The sound was most dominant at the rear of the engine, where the bellhousing meets.

Isolating the Source

Following service procedures, I separated the transmission from the engine just enough to pull the torque converter away from the flywheel. The engine was run again—noise still present. That narrowed it: the problem was in the engine itself, possibly the valve train.

Digging In

I dropped the oil pan, expecting to see signs of trouble—metal flakes, debris—but it was spotless. Continuing the inspection, I removed the valve cover, rocker arms, and pushrods to check for any raw mating surfaces from oil starvation. No problem found.

After reinstalling the pushrods and rocker arms, I rotated the engine to inspect proper lifter operation and measured lash—everything was within spec, and all lifters moved as they should.

Main cap bearings came out next—no excessive wear. The camshaft and lifters followed—again, no visible damage…