Searching for a Ram mechanic near you in Knoxville? Knoxville Auto Repair is the local alternative to the Ram dealership. We repair and service Ram cars, trucks, and SUVs across Knoxville, TN, gas, hybrid, and diesel, with honest, upfront pricing.
Ram repair near you
Our technicians know the Ram lineup inside and out. We use factory-grade diagnostic tools and quality OEM or equivalent parts, so your Ram is fixed right the first time, without the dealership markup or the wait.
A Ram with a tick at idle on the HEMI engine, or a diesel that drops into limp mode with a DEF warning, gets diagnosed component by component here rather than sold a bundled repair. Knoxville Auto Repair is open Mon–Fri 9:00 AM – 5:00 PM, closed Sat–Sun, and a truck that's down for work gets scheduled as a priority.
Ram trucks that come through the bay in daily work use show two patterns more than anything else: a tick at idle on the HEMI engine that gets worse if it's ignored, and diesel trucks dropping into limp mode over a DEF system fault with no warning beyond a dash message. Both get treated as urgent, because a work truck that's down isn't just an inconvenience — it's a day the owner isn't earning.
The dealer's fix for a DEF fault is usually a full system flush and a sensor replacement bundle, whether or not the sensor is the actual problem. Here the fault codes get read and checked against fuel and DEF quality first, because a contaminated tank or a bad batch of fluid throws the same limp-mode warning as a failed sensor — and costs a lot less to put right.
What's causing the tick at idle?
On the HEMI engine, a tick that's loudest at cold idle and quiets down as the engine warms and oil pressure builds usually means a lifter or rocker assembly is starting to fail. It's part of the cylinder-deactivation hardware that shuts down cylinders at cruising speed to save fuel, and those components take more wear over time than a fixed-valvetrain engine would.
Left alone, a failing lifter sheds metal into the oil, and that debris circulates through the rest of the engine. Caught early, it's a targeted repair; caught late, it's a much bigger job.
- A ticking noise most noticeable right after a cold start
- A noise that fades, then returns, as oil pressure changes
- Rising oil consumption between changes
- Occasional rough idle if a cylinder is misfiring
Why did my diesel Ram go into limp mode?
Limp mode on a diesel almost always traces back to the emissions system — DEF quality, a DEF sensor, or the exhaust fluid dosing itself — rather than the engine. The computer restricts power specifically to protect the aftertreatment system when it can't confirm the fluid or the dosing is working correctly, so the truck isn't actually broken in the way limp mode makes it feel.
For a work truck, the honest advice is usually the same: don't keep towing on it in limp mode, and don't assume a sensor replacement will fix a tank of bad DEF.
Is it safe to keep driving a Ram with a ticking engine?
For a short trip to get it looked at, yes; for towing or extended highway driving, no. A lifter tick that's ignored under load accelerates the wear and increases the odds of metal debris reaching other parts of the engine.
Do you work on diesel Rams as well as gas trucks?
Yes, both get diagnosed and repaired here, including DEF and emissions-related faults on the diesel side. The approach is the same either way — read what the truck's own systems are reporting before quoting a fix.
Can a work truck get scheduled quickly?
Call (865) 606-6602 and say it's a work truck that's down — that gets prioritized. Current hours: Mon–Fri 9:00 AM – 5:00 PM, closed Sat–Sun.