Ok, since I now have a good head on the Jeep, I've finally been able to use it as my daily driver.

I noticed what can best be described as a "slapping" sound when the engine gets to 2300/3000 rpm range before shifting to 2nd gear (and again when going to 3rd.) I haven't noticed it between any other gears. It is not present in lower rpm ranges.

It's definitely coming from the motor, so I am looking for thoughts on what I may want to look at it.

thanks, all!

 

Slapping or more of a knocking?

 

I would describe as a slap - it doesn't sound like anything I would consider a knock, and it only happens during higher rpms. I would think something like a knock could be heard regardless of engine speed.

It almost sounds as if the valves are slapping against the valve cover (but I know that is not the case, just trying to describe the sound).