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.

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[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.

 

[TerryMason]

I pulled the rear driveshaft to replace the ujoints, but I'm seeing some play in it.
This is a Cherokee front driveshaft that I had cut down by a driveshaft shop several years ago.

Does this look like too much play?

If I fully extend the shaft, there doesn't appear to be any play.

Additionally, does this fully separate - as in two pieces? I gave it a good tug, but it didn't come apart.

 

[Jeepergeo]

I could see maybe left to right engine roll with worn mounts. Forward and backward would surprise me.

Check that fan and serpintine belt loop and pullies to see what is moving the fan to the radiator....or....is the radiator loose and moving into the fan?

 

[TerryMason]

I've ordered new rubber mounts, that should be hear in a couple of days, along with my new shroud. I'll probably try to lower the shroud half an inch or so.

I've been researching my rear driveshaft, and from what I read a bit of rotational slop between the two halves is to be expected. I'll clean and lube it a bit and see how it feels.

 

[JPNinPA]

I've been researching my rear driveshaft, and from what I read a bit of rotational slop between the two halves is to be expected. I'll clean and lube it a bit and see how it feels.

Nice!


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

 

[TerryMason]

Nice!


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

I keep going back and forth on it, and I can't get a good feel if that's a normal amount of slop or too much.
I even priced out a new Tom Woods shaft at $429..

What do you think, is it worth replacing?

 

[superj]

Tons of pwoplw run th3 cherokee ones luke you are without issue. I say greae it amd put it back on and see how it is once your other little things are fixed too

 

[TerryMason]

I replaced my 15-year-old engine mount bushings with some brand new brown dog brand bushings. I even gave the mounts a new coat of paint. The old bushings were torn up and the passenger side was wallowed out. Definitely allowing the engine to droop

Freshly painted and installed

Once the engine mounts were fixed. I installed my new OEM fan shroud. I test fit it and it was still way too close to the bottom of the fan so I drilled new holes that dropped it down a half inch.

There's now about 3/4 of an inch between the fan and the bottom of the shroud

As to the rear drive shaft, while I was taking it apart, it didn't move smoothly and I found that the centering yoke had no grease in it and the needle bearings were just laying in the bottom. I could have bought three new u-joints and another centering yoke but instead I decided to just buy a Tom woods drive shaft. I'll keep my old one as a spare. The new shaft should be here later this week.

If you look close, you can see the pins laying in the center of the yoke. No grease to be seen...

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