Unusual Front End (Axle) Noise

snicklas

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OK fellas, I've been chasing this one for a bit, and am needing a fresh brain to ponder on it. I have looked, and not gotten any definite answers (and afraid to post it on fb, because I am sure like the last time I said something about an issue, I was told it was bad head gaskets, which it most definitely was not!!!!)

Had an issue, back in July, this was a 90+ degree day, I was on the interstate, doing ~55-60 and I crossed a "bridge lip" where there is a slight gap between the road surface, and the edge of the bridge surface. In this case, there was a slight difference in height between the road and the bridge. So there is a nice straight, sharp jolt introduced into the suspension, almost with a bang.....

Something like this......

xP1010081.jpg


After hitting this joint, there was a loud buzzing noise, very much like a failed bearing would make. I crossed the bridge and went over the expansion joint on the other side and it immediately quit making the noise. I exited the interstate at the next exit, less than a mile, and stopped in a parking lot. I looked over the underside of the truck, in the wheel wells to make sure I hadn't picked something up.... and I saw nothing. I popped the covers off over the lugs and hubs, and felt the outside of all 4 hubs, the floaters in the back, and the lockouts in the front. The passenger side was warmer than the drivers, so I very carefully drove the 9 miles home, at a slow pace and made it just fine with no issues or noise.

Raised the front, and removed the wheels, brakes and rotor, so that I was down to the bare hub. The drivers side was nice and "tight" with almost no noise (these are the factory unit hubs with 150,000 miles on them). The passenger side was still tight, but it did have a bit of a grumble to it..... I also have an ABS light on, and the Speedometer still works, so I figure it is the hub failing (as they do, it fouls the sensor and/or the tone ring will start to wobble). So I pull everything apart, find the passenger side in a bit of rough shape, and the hub vacuum seal needing replaced. The drivers is in good shape, but I messed up a stud removing the hub from the knuckle, so 2 brand new Timkin Unit Hubs were installed, everything was given a nice dose of anti-seize so it will come apart easier next time. Put the truck back on the road (still need to replace the knuckle seals) but all is good, except I still have the ABS light...... the front is nice and quiet, and no more odd noise...

Fast forward to around Christmas. I am headed to work, and the truck has been my daily driver since I replaced the unit hubs. This was a day in the teens to low 20's. Same scenario, on the interstate, hit a bridge expansion gap, and bam, and immediately the same buzzing noise. Hit the other side of the bridge, it quieted to about half a loud, crossed another an silent..... There are several bridges in this area of I-70 near downtown Indy and I was in morning traffic.... so I "was where I was"... Crossed another down the road a bit, but I had worked into the very right lane and as soon at it made the noise I headed for the shoulder. I was at speed when I got on the shoulder and when I started to slow down, when I reached ~25-30 the noise stopped. Hit the throttle, back up to speed and all is good. I cross one last bridge before my exit and it started again, as I coasted down the ramp, the noise stopped, and that was the last time I heard it.

I drove home that evening and went "through town" as to avoid the interstate speed and the expansion joints. I looked over everything I could think of in the front. I checked the tires (which were rotated between the 2 different times the noise occurred) the hubs, the axles, the lockouts, all the tire rod ends, the drag link, the shocks, the springs, the steering stabilizer and the bushings I could see... and nothing seemed out of sorts. The shocks are newer Bilsteins, the Hubs are Timkin, the tires are ~1 year old Firestone Transforce A/T's and all the other components are factory except the ball joints, and they were replaced several years ago with Moog, and all the front end grease Zerks have been greased regularly, and have taken grease. The rotors are starting to show some signs of warping as they are factory, but the brakes have been replaced once, with Wagner Thermo-Quiet pads.....

I have driven the truck daily since, but have stayed off the interstate. I have driven on rough roads, and have approached the same speeds I was running on the interstate without the noise reoccurring. Also, when we got our first real snow a couple weeks ago, I locked in the front hubs since the ESOF is still inop because of the knuckle vacuum seals. Did not get this noise, or any other odd noises the entire time the front axle was turning due to the lockouts being locked (the transfer case was in 2wd, so I was just "pushing" the front end down the road).

End of last week, the weather turned "nice" (near freeing and no precip) so I unlocked the hubs again. Then, today, I was moving fairly slowly, I was slowing down as I was entering a small town and was going around a slight curve, and the noise happened once again, for less than a second.... I was still slowing down and it just went silent again, like before.....

This is getting frustrating, as nothing seems out of order, the steering is still fairly tight for 161,500 miles, I am running stock sized A/T tires on factory rims, and running all factory leaf suspension at factory height.

I DO NOT believe that it is "Death Wobble" as there is absolutely no oscillations/wheel jerking AT ALL. The only think you can "feel" when this occurs is a vibration in the floor. It "feels" rotary in nature, and the frequency of the sound does change with speed (it is a fast whir at highway speeds, and is a lower slower rumble as you slow down).

Sorry for the long post, but I am just looking for some direction on what it could be.......
 

DaveBen

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You say it feels rotary in nature. This leads me to think the right hand wheel bearing is shot or going. I know these are not cheap, as I bought a spare just for this sort of thing. I am at a total loss to explain the on/off sounds you get when you hit a bump. You have enough miles on your truck that trying a new wheel bearing would not be out of line. I hope this fixes it Scott.

Dave ;tu
 

snicklas

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I hope not, both front hubs are about 6 month old Timkin's with about 10,000 miles on them. Could they go bad that quick?
 

snicklas

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OK, here is an incremental update on my noise.

Talked with a buddy at work who is a Jeep Nut (so much so the license plate on his TJ is "JEEPNUT") and he and I were discussing this today. With his 4x4 habit, is is friends with the fella who runs the shop at our local 4 Wheel Parts shop. He was talking to him already about some "Jeep Stuff" and he asked about my noise.

The fella told him, to have me replace the passenger side knuckle U-Joint and the Knuckle Vacuum Seal (the one that goes bad and makes the ESOF Hubs not work) (he also recommended doing a "vacuum delete" and putting "real" lockouts on it). So I am going to order a set of knuckle seals, and replace the U-Joints in the front end (he also has a "driveline guy" that has all the easy tools to swap out U-Joints).

What is happening is, as all the components wear, their tolerances open up a bit, not to the point of being bad, just loose. When the vacuum seal failed, and the unit hub, it caused the vacuum seal to "wobble out" (which this seal doesn't support the axle, but it does take up some room and makes things tighter) and the "bearings" in the U-Joint wear and open up, it allows the axle shaft to droop as it crosses the truck. When you hit a bump, just right, it allows the axle to bounce and will wedge in the lockout and the axle shaft will wobble instead of spin in a straight line. Once I slow down, the centrifugal force get to the point it won't hold it where it is, and it pops loose and quits spinning.....

So, I have some parts to order and install, and I will report back what I find........
 

snicklas

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OK, Fellas,

Does anyone have the part number for the Axle Hub Vacuum Seal..... I'm having trouble finding a part number to be able to cross reference. Or am I lucky and this is a Ford/Dana-Spicer only part?

I found a whole kit, which for the price contains a good amount of stuff...... but........
 

snicklas

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OK, Finally getting back here to wrap this one up. Between having to wait on the tax check, finding/ordering parts and my buddy and I having a free weekend at the same time, this took a bit to accomplish.

So, I ordered the new vacuum seals, o-rings and needle bearings for the hubs (just in case), new brake rotors and new Wagner Thermo-Quiet Severe Duty brake pads.

This past Saturday (03-12) I got to my buddies shop and started the tear-down. Pulled the wheels and brakes off, setting the old brake parts aside, pulled the hubs and was ready to pull the axle shaft from the housing. When I grabbed the stub shaft, on the passenger side and started to move it around to get it out, I noticed the knuckle rock back and forth a bit.... SON OF A B***H!!!!!!!!! Had my buddy verify, and sure enough found some slop in the ball joints..... Hadn't even taken the tire off the drivers side, and we walked over there and wiggled the drivers side wheel... and flop, flop, flop..... OH JOY.... well, look up and order ball joints..... so this has now just turned into a much longer day than I had planned.....

Finish pulling both sided apart and remove both axle shafts. Find that both vacuum seals are TRASHED, they actually came out in pieces....... loaded the axle shafts up and took them to "His Guy" for driveline work, to have the U-Joints replaced. Got the joints replaced with SPICER joints. The old ones were still in pretty good shape, but it was this far apart... might as well replace them...... and paying a pro to replace the joints was worth EVERY PENNY!!!! He had both joints replaced and back on the bench ready to go back to the Jeep to go to the shop in the amount of time I would have been F-ing with getting the clips out.....

Run and pick up the replacement ball joints (not the best ones, but what I could find on short notice, and much better than what I had)..... head back to finish up.

Removing the bad ball joints from the knuckles was about as much fun as you can imagine.... took at least 2 hours to remove and replace the 4 joints from the knuckles, with the proper tools...... they are just a B***H!!!!!! Put the knuckles back in, axle shafts and new vacuum seals (the reason we are here in the first place), hubs, new rotors, pads and hardware, wheels and put it back on the ground......

DRIVES LIKE A COMPLETELY DIFFERENT TRUCK. Almost no noise from the front (the clunk I was trying to figure out) and no "Original Unusual Noise" that I was chasing.

I still need to replace the drag link and tie rod as all the joints are starting to have a bit of play, which is more noticeable now that everything else is nice and tight..... and I have to replace the passenger side lockout. I somehow exploded the guts of the lockout, so now I just gutted that one for now to use as a "cap" on the hub. Still trying to decide if I want to spend the money on a stock replacement (the vacuum one for the ESOF, which will work properly now that I have done all this other work), or get a set of WARN/Mile Marker/ETC manual lockouts. This bad lockout also explains why I couldn't 4x4 to work when I needed it a few weeks ago....

So between the seals/u-joints and the ball joints, I have cured all the noise in the front......

Just wonder now if what I was having happen was a "mini death wobble" since the ball joints were loose, and I caught it before I had a MAJOR issue......
 

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