I have an '01 Durango SLT 4.7 with a new engine. It makes a mild clatter sound when reving under loads above 3200 rpm. I noticed it a lot yesterday as i came back from a road trip on I-95. I had to accelerate crisply several times to keep up with traffic and it made it every time. It has done it since the new engine was installed. I haven't gotten a CEL. Thoughts?

 

Spark knock, engine knock, pinging, detonation, goes by several names. Numerous causes.

 

The new engine only has 17k on it (it is a rebuilt unit from CME not a used/junkyard motor). When installed it got new plugs, water pump, radiator and hoses.

I drove it today and tried to replicate the issue. It only does it at highway speeds and under load when it kicks down to a passing gear.

What are common issues with these trucks?

 

To verify it's detonation, you could try a tank if hi-octane gas, which only exists to not do that.

 

As JeeperDon suggests, run a tank of 93. Add some Lucas to it. Report back.

 

While detonation hasn't been a problem for me, I did discover that these 4.7's do really prefer a min. of 87 octane gas (no advantage to going above 87 though, just the lowest that it really likes). Our regular here in Denver is 85, and I ended up with a tank of premium once because the gas station was out of regular gas. I noticed the engine did run much better. I've always before that run 85 because I didn't honestly believe these engines really needed anything more. I really notice the difference during the conditions you mention noticing issues at as well.