Another noise from under my TJ

[TerryMason]

You guys did such a good job diagnosing the "laughing monkeys" that I'm back with another.

Driving down the road in my 2005 Jeep TJ 4.0L automatic. When going around 50 mph, and with a wall or car next to me, I'll hear what to me sounds like a paper flapping in the breeze. It only happens when I'm pressing the gas, and stops immediately if I take my foot off the accelerator.

Driving down the road with nothing next to me to reflect the sound and I can't really hear anything (it's much quieter).

The sound in person is more rattle-y than the video lets on. In the video it sounds like a higher pitch moan.

What do you guys think, could this be a transfer case chain? This is easily reproducible, and since it's been happening I've removed the front driveshaft, and replaced my oil pump / OPDA.

 

[JPNinPA]

I would check how much engine and trans movement you have under load. Stopped, foot on brake, go from drive to reverse and back while watching how much the engine rocks. It could be the u-joints when the engine is out of alignment from wirn motor mounts.
Also check rear control arms. For the same reason. The rear axel may be torquing from a relaxed position to a position placing pressure on the u-joints.


Never look down on anyone unless you are helping them up - Jesse Jackson

 

[TerryMason]

I have brown dog extended engine mounts, so I went to roll around under my Jeep and take a look at them when I saw this.

I'm not sure if it's the cause or the symptom but it certainly isn't right. I've ordered a new (used) OEM shroud off eBay, but I may try running without one until it gets here to see if the noise goes away.

Looks like your guess of engine movement may be spot on.

Sent from my Pixel 6a using Tapatalk

 

[superj]

Oh, hungry fan got the shroud

 

[JPNinPA]

Check the fan too if the clutch is gone.

Dont drive too long without the shroud. Or at least monitor your engine temp. Sitting at a light or less than 30 mph could cause it to spike.


So how did you not hear the first crunch????

Never look down on anyone unless you are helping them up - Jesse Jackson

 

[TerryMason]

The fan clutch was replaced last year, but I'll check it out. I've also ordered some new motor mount bushings.
Haven't really driven it, once I realized I'd have to take the fan off to get the shroud out, then redo it again later when the parts came in, I decided to wait. I'm going to replace the ujoints in the rear driveshaft this week while I wait for parts, then replace the shroud with a new one.

As to how it happened, I would guess that it happened during my Feb/March trip to WV. I got stuck several times in deep mud, and I wouldn't have noticed if it happened then. Could be wrong though - the Jeeps so loud that I'm hard pressed to hear anything.