Not sure if this is common, but whenever my 08 JKU is under stress (low rpm and working hard) there is a loud ticking/clattering sound from under the engine.

For example climbing up a steep rock or pulling out of a mud hole.

Is this common or do I have something loose?

 

In 4lo? its normal to hear some clattering as the driveline slop is taken up by applying power and removing power.

However if its REALLY loud could mean you have something broken or worn out.

 

No, no problems in 4 low just in 2wd and 4hi when the rpms are low and stressing.

 

Your description sounds like it could be detonation / spark-knock to me.. I wouldn't normally call that noise loud, but it certainly is noticeable..

 

It is loud, kinda sounds like...

http://www.youtube.com/watch?v=JHFXG3r_0B8

but a little faster... I will try to post an actual video of what is does this weekend.

 

I have the same problem. Does it occur when you are trying to accelerate from a slow speed in a higher gear?

I figured mine was broken welds on my heat shield but I would like to hear other opinions.

 

Sounds to me like spark knock as well...