Strange Rumble

[hectikart]

So recently I've noticed what I can only describe as a strange rumble/vibration that only happened while I am between 50-55mph. It's not severe, but definitely can be felt, by me at least...when I have passengers they don't seem to notice it. It almost seems like the engine is revving up and about to shift, but there is no drop in RPMs when it stops, as if it had shifted....just everytime right at 50mph I start to get a rumble, and at 55 it is gone.

Doesn't matter if I am accelerating fast to get on the highway, or just driving at a constant 50mph. I believe it is only when my foot is on the gas though...not positive, but if I remember correctly, if I'm going say 52, and take my foot off the gas the rumble will stop.

My first thoughts were CV's and u-joints. My rear u-joint only has 10,000 miles on it, and the front was in good shape when the rear was changed. I haven't checked the CV boots yet, but it just seems odd to me that it only happens in a 5mph window. Any thoughts? I am due for another alignment after doing my lift, maybe that has something to do with it. I get a little vibration/steering wheel shaking at 70-75mph sometimes.

 

[Porkchop]

Tire balance maybe rotate tires see if shakes in the wheel goes away. Had to rebalance one of my tires after about 6 months noticed it when I did a tire rotation felt it in the steering wheel. I did notice that little vibe at 50 55 but not that much to worry about as the tire was in the back at that time and Duratracs were brand new. The wheel weight moved a little on the rim or I scewed up and was just off when I balanced it sometimes they can just come off as well.

 

[Luke]

Sounds like the same issue Rocky Mountain and I have... changed my u-joints.. no difference. Removing one set of rear iso's to sit at 22 instead of 22.5 made it almost disappear. Loading the back with several hundred pounds makes it dissapear completely.
I had the rear end components inspected at the dealership and got a clean bill of health. :shrug:

Can you see it in your rear view (ie headlights shaking)

The only thing that makes sense to me, is that it doesn't like the pinion angle.

P.S. It started happening after I installed the lift with my Silent Armors and with the new Duratracs.

 

[hectikart]

Thanks for the info. I'm getting new duratracs hopefully in the not too distant future, so at the same time I'll have them balanced and do an alignment...Hopefully that will take care of it. I'm only sitting at about 21.5, maybe 22 at the most in the rear. I haven't noticed any shaking in the rear view mirror.

 

[Luke]

When I am ******* the skinny pedal btwn 80-90 kph...(55ish mph) if someone is behind me I can see the vibrations in the rear view.

I've had more alignments in the past 4 months than in my entire life. :happy175: She drives straight, no complaints there.

Your at the same height in the rear as I am... I assume this started only after you lifted?

 

[hectikart]

yeah, started pretty much after the lift. It's the least of my problems now though....I broke down and had to get towed today. Same exact thing happened again that led to my $2800 upper engine rebuild 3,000 miles ago!! Started running rough out of nowhere, check engine light started flashing. Pulled over immediately and called the tow truck!

 

[WickedBruce]

Sounds like your having my kind of luck there Hectikart

 

[hectikart]

Sounds like your having my kind of luck there Hectikart

lol yea, except I wish I had flipped it over a guardrail so I could get the insurance money....I feel bad wishing death upon her, but Libby and I are not on speaking terms right now.

 

[WickedBruce]

Is the shop going to fix that sh*t for free? If not, I'd be throwing down haha

 

[rockymountain]

Ah, another 50 mph vibe. I'll go out on a limb here and say they ALL do it. It just matters if you are aware enough to notice it. I gave up. I drove an 05 for a test drive once, it did it too. My '03 also did it. Oh, and I also test drove an 05 rene, it did it. I settled for mine with 3000 miles on it which at the time did not do it. It started at about 38K I think. I really believe it is within the front intermediate shaft and cv half shaft. That or its that plastic axle bearing they are putting in the right side of the front diff. I bet the only KJ's that don't do it are maybe 02s or converted SFA KJs.

 

[hectikart]

Yeah, seriously they better...The mechanic who worked on it is on vacation until Tuesday. So I'm not even sure if it will even get looked at until next week. The shop has a good reputation and they've been in business forever...and my whole family has been using them for a long time. So hopefully they'll take care of it.

 

[Luke]

Sorry to hear about your luck Hect... hope the shop will stand behind their work if that is the fault.

 

[hectikart]

Thanks, I hope so too. Last time this happened I could also smell exhaust, was having electrical failures, running so rough it was stalling out on me. This time it wasn't nearly as bad...I also shut it off immediately, whereas before I had to drive it for a couple minutes to get off the highway. So hopefully minimal damage was done.

 

[Luke]

Just a quick update for ya Hect ... my 50mph vibes turned out to be my new "unbalanced" Duratracs... Damn tire shop kids! lol

$100 later and no more vibes!


EDIT: Well ... forgot that I had a load in the back. The vibe is still there but less than before ... almost gone

 

[hectikart]

good to know. I just checked my tire pressure and added some to my passenger rear, because it was low...that helped with my wheel shake at 70mph+ still have the 50mph one though...although it may be less noticeable now. It's strange, comes and goes...or maybe I'm just getting used to it.