Jeffrey Stepnick

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I recently purchased a 2003 Wrangler Sahara. 4.0L 6cyl, 5 speed manual transmission NV3550. It has a rumbling noise when idling in neutral. Might still make the noise when driving but can't hear it over engine and road noise. The noise stops when the clutch is pressed. I come from a mechanical background so I think I know the cause, but would like another informed opinion. I think it's the transmission input shaft bearing or possibly a counter shaft bearing. Wondering if a the clutch throw out bearing could make this noise. If the throw out bearing, I would think the noise would happen when clutch is depresses and not at idle. But I could be wrong.

Anyone run into this, or have knowledgeable opinion?
 
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Chris

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I recently purchased a 2003 Wrangler Sahara. 4.0L 6cyl, 5 speed manual transmission NV3550. It has a rumbling noise when idling in neutral. Might still make the noise when driving but can't hear it over engine and road noise. The noise stops when the clutch is pressed. I come from a mechanical background so I think I know the cause, but would like another informed opinion. I think it's the transmission input shaft bearing or possibly a counter shaft bearing. Wondering if a the clutch throw out bearing could make this noise. If the throw out bearing, I would think the noise would happen when clutch is depresses and not at idle. But I could be wrong.

Anyone run into this, or have knowledgeable opinion?

The fact that the noise goes away when you press in the clutch tells me almost certainly that it's the throw out bearing.

Is that what you were thinking?
 

TJDave

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The exact same thing happened to my tj shortly after I first bought it. Took it in and it turned out to be the throw out bearing. Figured I may as well just do the clutch at the same time.
 
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Jeffrey Stepnick

Jeffrey Stepnick

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I was thinking it was a transmission problem because the noise stops when the throw out bearing has a load on it(clutch depressed). But apparently a throw out bearing can be noisy with little or no load on it. That would be great! A clutch replacement is much cheaper than a transmission problem. I too would replace the clutch not just the bearing. I have no idea how many miles are on that clutch.
 

Chris

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I was thinking it was a transmission problem because the noise stops when the throw out bearing has a load on it(clutch depressed). But apparently a throw out bearing can be noisy with little or no load on it. That would be great! A clutch replacement is much cheaper than a transmission problem. I too would replace the clutch not just the bearing. I have no idea how many miles are on that clutch.

Well, I think any way you look at it the transmission is going to have to come out, right? The first thing I would do is remove the transmission and inspect everything. It should be easy to tell once it's all removed if the throwout bearing is indeed worn.

If you remove it and find that the throwout bearing looks good, then I would take the transmission to a specialist and have them inspect the insides. I say that because even being a very good mechanic, the one thing I refuse to touch is transmissions and ring and pinions. Those sorts of things take a very special skill set and they're very easy to mess up.

To me it sounds like the throwout bearing, but once you get the transmission out it should be easy to rule that one out as to whether or not it is the culprit.

Unfortunately I think that the bottom line is that the transmission does have to come out no matter how you look at it.
 

astro-jason

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Does the rumbling noise sound like metal knocking, does it go away if you rev it up ? If so try putting light pressure on the shifter like your trying to put it in gear. If the noise goes away I'm gonna say its normal, Think of it this way the gears are looking for a place to go with your input untill then they are happy just sitting there rolling on the shaft.

If you remember the old muncie transmissions from way back when. Its the same thing, if it shifts fine I wouldnt worry about it.
-Jason
 
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Chris

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Intersting! I've never driven a manual thing so I guess I wasn't aware.
 
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Jeffrey Stepnick

Jeffrey Stepnick

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Thanks for the replies. I now have to agree with badlieutenant. I never thought transmission sound I heard was the sound of impending doom, just a little louder gear noise than I expected. Not my first stick shift, but it has been many years since I had one.

I decided to replace the clutch knowing full well I did not have the money for a transmission rebuild or replacement. I have replaced clutches before, including 4WD. I would end up with a new clutch and rule out any clutch problem. I replaced all clutch parts and the flywheel. The clutch was worn, throwout bearing a little noisy but not the problem. I could have made it through the winter but not much longer with that clutch disc. It took me about 7 hours by myself. I'm out of practice on an unfamiliar vehicle. Some stubborn bolts and part cleaning.

Now the fun part. Still had the noise. But now I had a vibration too! 3 days later, I took it apart again. I thought I may have done something wrong. Smashed the pilot bearing or something. Found nothing wrong. It had to be the new flywheel out of true. I put my old flywheel back in. It was in perfect shape. I only replaced it because I had already purchased a new one. Back together, vibration gone. Yea, a little pissed. Total R&R time 3 hours 40 min. still by myself. Cut my time in half.

Changed the gear oil in the transmission. 123,500 mile on the transmission and looked like original oil. Went for a heavier weight oil. Royal Purple 75-140. Noise about 1/2 of what it was. Seems reasonable now.

It really was not bad changing the clutch. You can actually get at most bolts, a few difficult ones. Transmission and transfer case are REALLY heavy though. Used ratchet tie down to strap the assembly to a floor jack. Way too heavy to lift by hand.
 
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Chris

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That's good news @Jeffrey Stepnick

I've grown up driving nothing but manual transmissions my entire life, none of which were ever noisy. However, I've never driven a manual Wrangler TJ so this is new to me. I guess the manual transmissions on these things for whatever reason must make noise from the factory, good to know!

I've changed a lot of clutches in my life and some of them really, really suck to do. The Wrangler seems like it has enough room under it to get to most of the stuff you need to without being a royal pain in the butt. I can however agree that the transfer case and everything are insanely heavy, that's for sure!

Glad you got it sorted out!
 

Jerry Bransford

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Yes it's pretty normal for the various manual truck transmissions used in Wrangler TJs to make a noise when they're in neutral. It's usually just the normal sounds of the transmission's input shaft and bearings being spun by the engine when the clutch pedal is up. Step down on the clutch pedal and the transmission is no longer being spun by the engine so things get quiet. :)
 
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badlieutenant

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Glad you got a new clutch installed but sorry it didn't change any noise!

I first noticed it in 2006 when I bought a brand new from the dealer LJ. My current 2006 LJ Rubicon makes the exact same noise the off the showroom floor LJ did. No worries!
 
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StG58

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<snip>

If you remember the old muncie transmissions from way back when. Its the same thing, if it shifts fine I wouldnt worry about it.
-Jason

The old Muncie M21's and M22's. We called a modified M22 a "rock crusher" for a reason. Not because it would crush rocks, but because it sounded like it WAS crushing rocks. :eek: :D
 
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MBJ

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I've driven clutches most of my life. My 2005 TJ (6-speed NSG370 manual transmission, bought with 78K miles this past June 2015) has the sloppiest clutch of any vehicle I've driven, though one gets used to any vehicle. It clicks when the clutch is depressed and particularly when shifting in 1st and 2nd. It's not a smooth shifter into 2nd or reverse. I've read about the clicking and people point to the clutch linkage where it goes from the top of the pedal, through the firewall and into the master cylinder. However, most say it is benign.

I know it's a different problem, but I'm curious for any feedback. Is there basic maintenance I should be doing before things get worse? or is it just normal?
 

Stinger

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I've driven clutches most of my life. My 2005 TJ (6-speed NSG370 manual transmission, bought with 78K miles this past June 2015) has the sloppiest clutch of any vehicle I've driven, though one gets used to any vehicle. It clicks when the clutch is depressed and particularly when shifting in 1st and 2nd. It's not a smooth shifter into 2nd or reverse. I've read about the clicking and people point to the clutch linkage where it goes from the top of the pedal, through the firewall and into the master cylinder. However, most say it is benign.

I know it's a different problem, but I'm curious for any feedback. Is there basic maintenance I should be doing before things get worse? or is it just normal?

Mine did the same thing. I eventually quit noticing it. I didn't say it went away.:)
 
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