Terrible Rumble Over 40mph when foot OFF gas

[Overlord475]

Hey guys,

I'm having trouble pinning down the source of a loud vibration/rumble I'm getting while my foot is off the gas pedal at anything over 40mph.

There is no steering wheel shudder, and breaking seems to have no effect.

It is a rotational noise that coincides with the speed of the car.

If I go over 40 and start to slow down the rumble will last till I stop, with a slowing frequency.

I got under the truck last night and there is nothing blatantly obvious sticking out.

The U Joints seem to be in good shape and all the wheel bearings are tight.

I'm starting to think I need to further look at my rear suspension as I've noticed that the tread on my rear passenger tire is rapidly wearing.

Perhaps my lower control arms? I don't think the upper A control arm would cause this.

The rumble is LOUD, almost sounds like one of the control arms bolts is lose and the arm is just banging back and forth once I hit a certain vabration due to speeds over 40mph.

Thoughts??????

 

[Bullwinkle]

Hmmm
This sounds like the same issue that I've been trying to figure out. I have no idea what it is either.

 

[NJallDAY]

First thing that comes to mind when you say coincides with rotational mass is hub bearings. Can you pin point if its coming from a specific corner of you jeep? And how did you check the bearings? If you jack up one side at a time and get the wheel spinning and hold the spring with your free hand you can usually feel the vibrations. Or maybe your wheels went out of balance. You could also have a bad cv axle.... i currently have a bad one and it shows no signs of damage other then making noise, only way i figured it out was trial and error and a little back and forth with Mr. Mudd. Changed the hub bearing and the noise remained.

Edit: just re read your post. You say its almost like the control arm bolts are loose, so did you check them? If its really banging around im guna say its either u joints or a bad cv.

 

[tjkj2002]

Sounds like bad u-joints.

 

[WickedBruce]

I have the same thing and it is my U-joint.

 

[Bullwinkle]

Ok thx guys, I'll check that as soon as this Snow Storm of the Century is done and gone LOL

 

[JeepJeepster]

That's exactly what my jeep was doing when the intermediate shaft was going bad on the passenger side. Made noise when I let off the gas, never understood why, and also made noise when I was driving slow in parking lots and such.

 

[Overlord475]

I have the same thing and it is my U-joint.

Both my U joints are fine. No play in them at all.

I did find a tear in my inner passenger side CV boot though:

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Looks like it's leaked a good amount.

I know normally I should be able to make a slow hard right had turn and here the cracking if the outer boot is shot, but with it being the inner boot I'm not sure.

Any way to tell for sure that this is my source with it up on jack stands?

I plan to take the wheel off today and check for play in the shaft.

 

[Cardhu]

drop rear drive shaft off pinion (4 bolts) and rotate the flange yoke in your hand and feel if its rough. mine had no play even after they were toast and dryer then a bucket of sand.

u joints are cheap and a good place to start before you go through the rest of the list.

as for rear tire wearing, if your rear lca bushings are shot it will mess with your thrust angle.

 

[Akedos]

I know it may sound silly, but check all your lug nuts too. It's possible one of your tires is loose. While under acceleration there won't be rumble, but while coasting it will shake because there is no force from the hub onto the rim. Easy thing to check too.

 

[JeepJeepster]

At the base of that boot you're showing in the pic, grab the steel part and move it up and down and back and forth. If there is excessive play there, your intermediate shaft splines are bad.

Edit: by the base I mean the big side (diff side).

 

[Overlord475]

In conclusion,

It was my driveshaft u-joint making all the noise.

 

[ciancca]

Thank You Thank You
The vibration and noise frightened me yesterday, and I joined this forum to seek advice. Thinking it may be CV joint issues or U Joint issues...I went outside to my truck and found FOUR loose lug nuts on my drivers side rear tire. What was with that??? anyhow..Tightened the nuts...noise all gone!!
thanks again
Cec

 

[uss2defiant]

Thank You Thank You
The vibration and noise frightened me yesterday, and I joined this forum to seek advice. Thinking it may be CV joint issues or U Joint issues...I went outside to my truck and found FOUR loose lug nuts on my drivers side rear tire. What was with that??? anyhow..Tightened the nuts...noise all gone!!
thanks again
Cec

torque it to spec 110 ft-lbs

 

[LibertyTC]

ciancca, I am glad that you were able to discover a very dangerous condition & correct it.
When I had the OEM stock lugs with the plastic caps, not good. Loose often.
I replaced all the Lugs with McGard lugs and all is well.
I still keep the 1/2 inch torque wrench in the Jeep & check the lugs frequently!
50437[/ATTACH]"]

You must be registered for see images attach

^ Buy a torque wrench if you do not own one and use it.
Anytime a wheel has been off withing 50 miles is should be checked.
I do mine once a week or anytime before & after offroading!

 

[erikblacksa]

Hi Guys
I'm having the same problem with mine.. I jacked up my car last night and found the rear wheels can move in and out slightly, both of them.. I tried dismantling the hub but got stuck at the last step of trying to get the hub off to see the bearing.. I did see 4 bolts which you can only get to after you have taken the drum breaks off but didn't attempt to take that off. Is there maybe a circlip holding the hub on? Excuse my ignorance...

 

[Porkchop]

Did you back off on the star adjuster? Access is in the lower back side of the backing plate, little oval window with a rubber cap covering the hole.

 

[MauiJeep]

Front end noise fixed

I have a 2005 4wd that had horrible front end noise. It ended up being the front C/V joints and the front bearing assembly. I did both sides. Its like night and day!

 

[tom0826]

Hi Guys
I'm having the same problem with mine.. I jacked up my car last night and found the rear wheels can move in and out slightly, both of them.. I tried dismantling the hub but got stuck at the last step of trying to get the hub off to see the bearing.. I did see 4 bolts which you can only get to after you have taken the drum breaks off but didn't attempt to take that off. Is there maybe a circlip holding the hub on? Excuse my ignorance...

The rear wheels are supposed to move in and out a little with c-clip axles on the Liberty. If youre trying to get at the wheel bearings you need to pull the axle shafts.