2009 Chevy Trailblazer 4.2L L6 is clunking at 2000 rpm. The noise gets softer not louder at 30mph when I press the gas. Oil pressure stays steady at mid-range. I changed the oil and filter. Hoping its loose torque converter or something, and not rod.

Can you guys steer me right? Thanks.

Here is the video
DMVB5Md2vpM_Brio5g8q https://www.youtube.com/watch?v=Lo0wGcZvdew



  • Welcome to Motor Vehicle Maintenance & Repair! Commented Apr 18, 2019 at 11:43

1 Answer 1


I hate to say it, but that surely sounds like a rod knock to me. It's hard to say 100% that's what it is (diagnosing over the internet being what it is), but two things are telling me this:

First, when you first started the TB, you could hear the knock until the oil pressure caught up. That low pitched sound at first start up is never a good thing and stands out as an issue.

Second, the low pitched sound continues when you rev up the engine. It sounds like someone is hitting the block with a sledge hammer, putting it right in the ball park of a rod knock.

This is not going to get better on its own. You are either looking at a rebuild or a replacement.


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .