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-   -   Vibration at 2200-2500 RPMs (http://www.jeepforum.com/forum/f9/vibration-2200-2500-rpms-1519544/)

sardog12 05-06-2013 02:48 PM

Vibration at 2200-2500 RPMs
 
I am having a new issue (or if it isn't new, it wasn't as noticeable previously) where I am getting a fair vibration with the engine turning at about 2200-2500 RPMs, regardless of whether or not I am moving. I have not noticed anything outside of this range, either lower or higher RPMs. I can be driving or sitting with the clutch depressed and revving the engine and the vibration will still occur. I have had the engine replaced (with another I6 4.0L, approx same mileage-50k) approximately one year ago due to excessive water in it and, at the same time, I had the clutch changed. I had to bring it back shortly after since the throwout bearing was ticking and the throwout bearing was changed again. I have not performed any other maintenance on the engine except for the routine oil changes and have only put approximately 6-7k on the engine since.

I have done searches and many seem to point in the direction of the torque convertor (bolt being loose) or a motor mount. However, I didn't think that a manual transmission has a torque convertor. Are there any other ideas of things that I could look for which could be causing this?

Ironhead 05-06-2013 02:50 PM

how are your motor and trans mounts?

bobjp 05-06-2013 02:56 PM

Correct, manual transmissions do not have torque converters.

Look at everthing that the serpentine belt turns. Is there any excess run out on any of the pulleys? Feel if any of them are loose. Is the crank shaft pulley tight? Some have had those fail.

sardog12 05-06-2013 03:27 PM

Quote:

Originally Posted by Ironhead (Post 15396748)
how are your motor and trans mounts?

Thanks, I will check those. But could the vibration go away at higher RPMs with bad motor mounts?

Quote:

Originally Posted by bobjp (Post 15396776)
Look at everthing that the serpentine belt turns. Is there any excess run out on any of the pulleys? Feel if any of them are loose. Is the crank shaft pulley tight? Some have had those fail.

Will check these, too!

Ironhead 05-06-2013 03:34 PM

Quote:

Originally Posted by sardog12 (Post 15396954)
Thanks, I will check those. But could the vibration go away at higher RPMs with bad motor mounts?

yes, any time you have a spinning force, there will be optimal spinning rates and less optimal ones.

think of a u-joint going bad in a ds, most of the time, the vibes are only felt at a certain speed, because the shaft is spinning at a rate that is less optimal and is putting more stress on the u-joint



its no sure thing, but something to look at

sardog12 05-06-2013 03:36 PM

Gotcha, thanks.

sardog12 05-07-2013 10:12 PM

Checked the mounts and they all look fine. The tension on the belt looks good but I haven't gotten a chance to check to see if anything that the belt is on seems like it is having a problem.

I was recommended to check to make sure that the one or more of the bolts holding the flywheel hasn't worked loose since the clutch was changed when the engine was replaced last year. Looks like my weekend may be a fun one.

dauster500 05-08-2013 08:57 AM

Obviously it's very hard to help without seeing it but...do you think it could possibly be an engine missfire?

sardog12 05-09-2013 03:36 PM

I wouldn't rule it out however I brought it to someone to save time that I didn't have to troubleshoot it effectively. Of course, I didn't know that I was going to be let go from my job yesterday afternoon but that's ok. I am putting all of my time towards finding a new job right now.

sardog12 05-13-2013 10:33 AM

Got the Jeep back yesterday and they couldn't figure it out. However we have eliminated anything that is run by the belt and they said that they didn't see anything wrong with the crank balancer. So now I am looking into it again. At least I have been plenty of time since I am only job hunting right now.

bobjp 05-13-2013 11:24 AM

Did they look at the clutch? There's a cover on the front of your transmission that can easily be removed so you can at least see if there's anything out of the ordinary with the flywheel.

sardog12 05-13-2013 05:48 PM

Quote:

Originally Posted by bobjp (Post 15427133)
Did they look at the clutch? There's a cover on the front of your transmission that can easily be removed so you can at least see if there's anything out of the ordinary with the flywheel.

I haven't pulled the cover off of it but it looked a bit more difficult to pull off.

On another note, I spoke with a friend of the family and he said that he would first check the harmonic balancer as they sometimes slip. It looks pretty easy to get to however I don't know how yet how I would keep it from spinning while I try to turn the bolt. However, since I would also be possibly turning the crankshaft (?) at the same time, is there anything I should be concerned about if I try to pull and replace this?

bobjp 05-13-2013 09:12 PM

The harmonic balancer is the "crank balancer" you said the mechanic checked.

The transmission dust shield is not difficult to remove. I think you should do this next.

I would consider getting a second opinion. Engine vibrations that you can notice from the driver's seat should be easily diagnosed by a competent mechanic. Unless you told him only to look at the serpentine belt...

sardog12 05-29-2013 02:13 PM

Well, after more than two weeks and ultimately having to bring it to someone, I have an answer as to what it was. We changed the harmonic balancer as the rubber was beginning to crack but that didn't resolve it. The flywheel looked to be good as well. The problem was with the clutch, particularly with the pressure plate not being balanced. It was likely happening since the clutch was replaced last year and I just didn't notice it until recently or was thinking that the vibration I felt was a driveline vibration which I have been chasing and unable to resolve because I was incorrectly diagnosing it.

NotURMailman 05-29-2013 02:29 PM

Sucks you had to go through all that, but glad you got it fixed.


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