quikrich

I've tried finding threads about this and i found some help but not quite enough.

I have a 2001 Jeep Cherokee Sport 4x4 4.0, 3.5in tuff country lift.

It's making a loud noise/growl/loud hum/vibration from underneath my feet in what seems to be the transmission "area". It's pretty loud and noticeable to passengers. It almost sounds like if you were to make a spanish "R" roll sound in your mouth, but louder.(Best description i can get)

It does it only when i give maybe half to more throttle from a stopped position and then it goes away when i ween the gas pedal away or just accelerate slower. When it growls/vibrates like that it almost feels like it loses acceleration power.

Again, It only does if from the stopped position. Once i'm going 20mph or so i can punch it and it accelerates fine.

Any help would be great... THanks!!

Xjtim

U joints? Since its an 01, check the pinion angle of the front axle, all though, it shouldn't be too bad with a 3" lift...

quikrich

ok. I found this diagram. Where would you suggest to check? Thanks!

jebmccall

check ur driveshaft u-joints, slop in the driveline, what does ur driveshaft angles look like?

Xjtim

3,2,1 even 9...

cruiser54

First place I'd look is to see if the exhaust is hitting the trans/transfer case crossmember under acceleration. Very common. Usually caused by worn engine and/or trans mounts. Slide on under and take a gander.

jeepsurfer1

also even more common with a t case drop..
could it also be a major header leak giving off the sound and the vibes coming from u joints?

bambam0417

Subscribed! I have the same issue. Been checking stuff out but cant locate what ever might be making that noise. My xj is stock height so It isnt a lift issue at least for me.

spencer elliott

i think my XJ suffers from this also. only when going about 15 mph. doesnt matter if im accelerating or slowing down. it doesnt do it all the time, but often. id say growl is the most accurate sound. i feel the vibes from under my feet. definitely seems to be coming from the driver side. it is audible inside even with the radio on.

ive been trying to locate it for some time. my next attempt was going to be a steering box brace. could the steering box be vibrating?

Xjtim

Now that I think of it, I had the same issue, but it was the tail pipe hitting the shackles...I smashed it up out in the desert, it can rattle the pipe all the way up to the front, I think a couple of guys suggested this before me....and it was while I was accelerating, then it stopped

JerrytheJeep

Id check for u joints and slop in the driveline, I had a few burnt bearings and I had the same symptoms. Go ahead and grab hold of your driveline and wiggle it in all directions. It shouldn't move a whole bunch except in and out of the transfercase. Also if you twist it it should feel solid and move your jeep slightly with the parking brake off. Also check your pinion angle, 3.5" is borderline sye worth.

cruiser54

Check the clearance between your exhaust pipe and the crossmember.

quikrich

Thanks for all your comments!!

I'll check u joints, and driveline, and see if the exhaust is hitting the crossmember tonight when i'm off work.

There is a small leak between the block and the transmission i believe. It's not a big leak though... not enough to really even add more oil. After i drive it sometimes there are spots on ground and sometimes not, just depending on how long i drive it.(Don't think that's the issue, but could be wrong) I'll double check tonight to see where it's coming from &...

I'll keep you posted on what i find out.

cruiser54

The oil leak is not likely the cause. To determine the source of the leak, try this on for size.
I'd be looking up above first, and VERIFYING the source of the oil leak yourself. Many mechanics and friends love to tell you it’s the rear main seal. Has a catastrophic ring to it, doesn’t it? A simple leak at the back of the valve cover could produce the same symptoms. Don't jump on the RMS/oil pan gasket bandwagon just yet.

Almost any oil leak on your 4.0 is gonna drip from the RMS area for two simple reasons.
First off, the engine sits nose-up and oil will run back to that area. Secondly, the RMS area is also the lowest point on the engine. Simple physics and the old plumber's adage apply here. "$hit flows downhill".

Valve cover gasket, oil pressure sending unit, oil filter adapter seals and distributor gasket, in that order, have to be eliminated as possibilities first.
Revised 5-19-2012

quikrich

Okay,
Sorry it took some time to get back to you all...
I've been dealing with this lawsuit deal... and it's stressin me all out... but anyways...
So i've had a chance to look underneath my Jeep and check things out...

First, I checked the crossmember and exhaust pipe clearance, and there is a good gap of 2 inches or so. I don't think that is the cause... unless somebody says otherwise.

Second, I wasn't able to find anything real loose or sloppy as far the driveline is concerned.
Does it matter if my Jeep is in park or not?

As far as the Pinion angle, i checked it out but i'm really not sure what angle would be ideal... FYI, The lift has been on the Jeep for almost 3 years now.

I checked the catalytic converter as well and there doesn't seem to be anything loose there.

The leak from what i can tell is probably a valve cover leak. It doesn't seem to be rear seal. So, valve cover gasket isn't difficult to replace.

Any other thoughts guys? Thanks