Bad thowout bearing?

[TJ Starting]

My Uncle has had this noise from his 2000 TJ ever since he bought it. Been thinking about doing a clutch job with all the fixins to see if that resolves it but figured we might get a second opinion before we dig in. Only makes noise while clutch is depressed/letting clutch out, most obvious in first gear. Posting vid with audio if you can make out the noise best described as knife in marble.

 

[TJ Starting]

Video is from in skidplate.

 

[flyinfish]

Likely a throwout bearing if noisy when clutch pedal is depressed and goes away when not depressed.

 

[pagrey]

The video sounds like the bearing to me and like @flyinfish says, if it does it on cue that's probably the deal.

 

[AndyG]

My vote is the same-

 

[TJ Starting]

Ok, thanks yall. Sounds like we'll give it a try. I know the recommend clutch brand is LUK but if I remember right there was some discussion on the the different throughout bearings, does anyone know the recommendation on that is?

 

[L J]

does anyone know the recommendation on that is?

It's at the level of "best oil". There is no consensus. Some are fine with the plastic bodied LuK. Some prefer the metal bodied LuK. Some prefer a National. Etc., etc., etc.
For myself, I found the bearing itself, not the plastic body, of the LuK included in my kit felt cheap so I purchased a National.

 

[MikekiM]

Likely a throwout bearing if noisy when clutch pedal is depressed and goes away when not depressed.

Interesting.. I thought it was the opposite. Noise goes away when you depress the clutch. Mine chatters a little once it warms up, and only when the clutch isn't depressed. Goes away once I depress the clutch..

 

[Jerry Bransford]

Interesting.. I thought it was the opposite. Noise goes away when you depress the clutch. Mine chatters a little once it warms up, and only when the clutch isn't depressed. Goes away once I depress the clutch..

It is true. A throwout bearing is not doing anything until you step down onto the clutch pedal, it's bearing is not spinning until then.

 

[flyinfish]

Interesting.. I thought it was the opposite. Noise goes away when you depress the clutch. Mine chatters a little once it warms up, and only when the clutch isn't depressed. Goes away once I depress the clutch..

The noise is produced from the bad bearing when it is pushed against the clutch pressure plate by the clutch fork causing it to spin. When the clutch pedal is not depressed the bearing isn't spinning and the bearing won't make noise.

 

[06TJ35's]

Ok, thanks yall. Sounds like we'll give it a try. I know the recommend clutch brand is LUK but if I remember right there was some discussion on the the different throughout bearings, does anyone know the recommendation on that is?

The plastic throw out bearing works just fine. Don’t go out and buy a metal one if it comes with plastic tb

 

[Jerry Bransford]

The plastic throw out bearing works just fine. Don’t go out and buy a metal one if it comes with plastic tb

Not to mention the bearing itself is of course not made from plastic.

 

[06TJ35's]

Not to mention the bearing itself is of course not made from plastic.

Right!
I guess the majority of information out there is that plastic TOB doesn’t work when in fact it works perfectly fine.

 

[MikekiM]

The noise is produced from the bad bearing when it is pushed against the clutch pressure plate by the clutch fork causing it to spin. When the clutch pedal is not depressed the bearing isn't spinning and the bearing won't make noise.

I thought it chattered when the clutch is released because there is no load on it.

So, what might cause a chatter once the gear box is warm and the clutch is not depressed?

 

[Jerry Bransford]

I thought it chattered when the clutch is released because there is no load on it.

So, what might cause a chatter once the gear box is warm and the clutch is not depressed?

Transmissions used in our Wranglers can and normally will make a whirring rattling noise when in Neutral without the clutch pedal being depressed. Those sounds are from the input shaft and its bearings being spun by the engine.

 

[MikekiM]

Transmissions used in our Wranglers can and normally will make a whirring rattling noise when in Neutral without the clutch pedal being depressed. Those sounds are from the input shaft and its bearings being spun by the engine.

So no concerns?

I haven't noticed the whirling sound when out of gear..but plenty of chatter when warm. obviously, it is very noticeable once you start to move. Sounds a bit like a huge leaf blower.

 

[flyinfish]

So, what might cause a chatter once the gear box is warm and the clutch is not depressed?

I'd try a mechanics stethoscope or long screwdriver and pinpoint the noise if possible. Chatter is a term that is usually associated with the clutch disc to flywheel and pressure plate. Chatter can be produced by hot spots or other issues and is not something you normally hear of when in neutral and parked.