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-   -   Weird vibration (http://www.wranglerforum.com/f210/weird-vibration-6919.html)

ResQguy 03-29-2007 01:14 AM

Weird vibration
 
Hey guys...newb here. I just bought my first Jeep a week ago...a '99 TJ. Over the weekend, my buddies and I slapped a Rough Country 4" lift on it with some Mickey Thompson Classic II's (15x8) wrapped in ProComp Mud Terrains (33x12.5). It's going to be a daily driver and rarely offroad, so I wanted to save a little cash. Anyway, here's my problem. Today, I noticed a strange grinding/rattle/vibration coming from underneath. It only happens when it's in drive, and usually only when I'm stopped. The lift was easy to install (we're all helicopter mechanics in the Coast Guard) and it came with a transfer case lowering kit. I don't think the installation was the problem. Since I'm new to Jeeps, is there something I could check out before I break down and take it to a shop? Any input is appreciated.

4Jeepn 03-29-2007 04:43 AM

When you say its in Drive, to you mean as in the auto tranny in "d" or the manual in any gear? the manual is known to make a marbles in a can sound until the clutch is pushed in. Thus, where does the sounds/rattle feel like its coming from?

mrbigjeep 03-29-2007 09:57 AM

if it doesn't vibrate under acceleration it probably isn't a driveline vibe...may be just part of the "jeep thing" :D

ResQguy 03-29-2007 11:29 AM

Thanks for the responses. I guess I forgot to specifiy that it was an automatic. So, whenever it's in "D" it makes the noise. Honestly, I can't tell if it does it at higher speeds because of the road noise and all. The marbles comment was actually pretty accurate. It sounds exactly like a metal can full of marbles being swirled around whenever it's in "D."

ResQguy 03-29-2007 11:31 AM

Also, it sounds like it's coming from between the front seats, but that's just a guess.

Jerry Bransford 03-29-2007 11:55 AM

Maybe it's the catalytic converter heat shield vibrating against the cat or tub? That shield could have been bent a tad during the lift kit installation. Could also be the t-case shifter linkage rattling.

ResQguy 03-29-2007 12:00 PM

Quote:

Originally Posted by Jerry Bransford (Post 66716)
Maybe it's the catalytic converter heat shield vibrating against the cat or tub? That shield could have been bent a tad during the lift kit installation. Could also be the t-case shifter linkage rattling.

I thought about the cat convertor shield, but wouldn't that vibrate regardless of being in "D" or not? If it's the t-case linkage, is that serious? The lift we installed instructed us how to adjust the linkage in case we weren't able to shift into 4L. The noise is pretty loud. Not hole-in-your-muffler loud, but noticeable. The only reason I haven't been able to tell if it does it when I'm driving is because it's been so freakin' windy here in LA over the last few days and it's just been too loud inside. Like I said, I've only noticed the noise at stop lights and I'm in "D." The noise immediately goes away when I shift to "N" or "R."

1BLKJP 03-29-2007 12:04 PM

Are you getting any clunking when you shift into drive or reverse? My thinking would be maybe the tranny mount is loose and didn't get tightened down all the way?

erickpl 03-29-2007 12:07 PM

Catalytic converter on my 97 did the same thing. Made more noise at idle than when moving. When the jeep stopped and turned off, smack the converter with a rubber mallet. If it rattles, there's your problem. You get a different vibration from the engine/tranny when in drive and foot on the brakes than when moving, and that different vibe may be causing the catalytic to rattle funny.

Early TJ's have a known issue with the catalytic.

Jerry Bransford 03-29-2007 12:10 PM

Vibration in Drive vs. in Neutral is probably just a resonance thing where the culprit will vibrate at the lower Drive RPM but not at the slightly higher Neutral engine RPM. :)

ResQguy 03-29-2007 12:12 PM

Quote:

Originally Posted by 1BLKJP (Post 66721)
Are you getting any clunking when you shift into drive or reverse? My thinking would be maybe the tranny mount is loose and didn't get tightened down all the way?

Nope, shifts smoothly.

ResQguy 03-29-2007 12:13 PM

Quote:

Originally Posted by erickpl (Post 66723)
Catalytic converter on my 97 did the same thing. Made more noise at idle than when moving. When the jeep stopped and turned off, smack the converter with a rubber mallet. If it rattles, there's your problem. You get a different vibration from the engine/tranny when in drive and foot on the brakes than when moving, and that different vibe may be causing the catalytic to rattle funny.

Early TJ's have a known issue with the catalytic.

Nice. I'll give that one a try today. I don't work until 3pm today and I have a few errands to run before I go. Let's see if it gets worse...

ResQguy 03-29-2007 12:59 PM

Just got back from the grocery store. Ok, it doesn't do it as soon as I put it into "D" and take off. It takes a few minutes before the noise begins. Also, it sounds less like marbles in a can and more like a Huey helicopter from a Vietnam movie, haha. Oh, and it's definitely coming from the front somewhere...forward of the dash area and underneath. Any thoughts?

jp'rs_peep'rs 03-29-2007 01:03 PM

Check the exhaust system over.
Check out your install again.
Check the t-case shift linky.

C.

ResQguy 03-29-2007 01:07 PM

Quote:

Originally Posted by jp'rs_peep'rs (Post 66737)
Check the exhaust system over.
Check out your install again.
Check the t-case shift linky.

C.

While I was out, I made sure I was able to smoothly shift into 4H and 4L...no problems there. Also, I visually inspected the linkage...everything looked cool. My roommate and I gave the new lift a good once-over yesterday and didn't notice anything out of the ordinary. The exhaust, however, could use some work. I'm thinking that, because it takes a few minutes to start making the noise, that the exhaust system needs to heat up before it starts clunking.

Joe Dirt 03-29-2007 04:00 PM

If you didn't adjust the transfer case shifter linkage after installing the transfer case drop, it might be the transfer case shift fork rubbing. Adjust it soon or it will wear through.

ResQguy 03-29-2007 05:40 PM

Quote:

Originally Posted by Joe Dirt (Post 66788)
If you didn't adjust the transfer case shifter linkage after installing the transfer case drop, it might be the transfer case shift fork rubbing. Adjust it soon or it will wear through.

If that were the case, wouldn't it rub right off the bat rather than waiting 5 minutes or so into the drive to start rubbing? Also, don't know if I mentioned this...it doesn't do it in reverse, only in drive. Weird...

Triple88a 03-29-2007 06:14 PM

tranny drop?

ResQguy 03-29-2007 06:44 PM

Quote:

Originally Posted by Triple88a (Post 66825)
tranny drop?

Huh? :confused:

Triple88a 03-29-2007 07:15 PM

you drop the tranny/transfer case skid to lessen the angle from the driveshaft. With 4" of suspension lift you get quite of an angle which causes vibrations.. I think RC kits come with brackets but i thought i might ask

Joes 03-29-2007 07:55 PM

Quote:

Originally Posted by ResQguy (Post 66735)
Just got back from the grocery store. Ok, it doesn't do it as soon as I put it into "D" and take off. It takes a few minutes before the noise begins. Also, it sounds less like marbles in a can and more like a Huey helicopter from a Vietnam movie, haha. Oh, and it's definitely coming from the front somewhere...forward of the dash area and underneath. Any thoughts?

IF it sounds like a Helo from Nam i'll buy it from U..:D

mrbigjeep 03-29-2007 08:07 PM

Quote:

Originally Posted by Triple88a (Post 66825)
tranny drop?

it doesn't sound like a driveline vibe. but the roughcountry 4" lift does come with one

Triple88a 03-29-2007 08:54 PM

yeah i just saw he said he installed the drop bars

ResQguy 03-29-2007 11:19 PM

Quote:

Originally Posted by Triple88a (Post 66841)
you drop the tranny/transfer case skid to lessen the angle from the driveshaft. With 4" of suspension lift you get quite of an angle which causes vibrations.. I think RC kits come with brackets but i thought i might ask

Yeah, we dropped the transfer case.

ResQguy 03-29-2007 11:21 PM

After driving it around for a while and letting it vibrate, a bunch of the helo mechs at work took a look at it. It looks like the cat convertor is vibrating pretty badly. So, no big deal...I was about to slap on a new system anyway. Thanks for all the input guys.


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