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-   -   Troubleshooting bad Half Shaft/Steering Rack/Front Bearings (http://www.jeepgarage.org/f181/troubleshooting-bad-half-shaft-steering-rack-front-bearings-32942.html)

jayloop 12-22-2011 12:18 PM

Troubleshooting bad Half Shaft/Steering Rack/Front Bearings
 
Alright guys, I'm looking for some more expertise in troubleshooting a problem that is quickly escalating-
Symptom: Roaring/grinding noise, followed by intermittent metal on metal clunk.
When it occurs: not all the time, as I cannot always duplicate it. Here is what I have so far:
1. vehicle has to be moving
2. roaring is in harmony with RPM
3. mostly occurs when coasting downa after acceleration.
4. When close to a stop, it feels like something is grabbing the left front wheel.

What I've checked:
1. everything up front for tightness.
2. half chaft CV boots for leaks/signs of failure.
3. Put a vid camera under the car during the problem but can't trace exact source of the noise although it is in the front to left front area.
4. Searched "mysterious clunk" threads on the forum until I'm blue in the face.


I believe the most probable source would be the half shaft on the drivers side, but aside from tearing everything apart I'm wondering if any advanced mechanic type guys out there could assist me in further troubleshooting...

BTW, there were no changes made prior to the beginning of the noise. No heavy wheeling, no new parts, no teardown/put back together, etc. Just normal driving.

Thanks in advance for any input!

jlewissystem 12-22-2011 12:25 PM

Re: Troubleshooting bad Half Shaft/Steering Rack/Front Bearings
 
Can you jack it up and spin the wheels to ID where the sound is coming from? Maybe the wheel hub?

jayloop 12-22-2011 02:10 PM

Re: Troubleshooting bad Half Shaft/Steering Rack/Front Bearings
 
Good call!
I raised the front with a floor jack, spun the tires back and forth and found everything to be quiet EXCEPT for the front driveshaft, which sounds like a set of morrocas. It also has a "Pinging" noise in it that I've heard when the noise occurs. I'm pretty sure a driveshaft shouldn't be this noisy. I also tested by keeping a preload on the driveshaft while driving. Even when decelerating and braking, I continuously kept my foot on the gas until coming to a complete stop. While keeping this preload on the driveshaft I never got the noise again.

Now to decide whether to tackle myself or get it to a shop. Has anyone done this before?


jayloop 12-22-2011 03:20 PM

Re: Troubleshooting bad Half Shaft/Steering Rack/Front Bearings
 
Hmmm, another thing I just noticed is there is no boot on the CV joint at the rear side of the front driveshaft. Uh-oh.

jayloop 12-22-2011 04:07 PM

Scratch that...there isn't supposed to be a boot.

jlewissystem 12-22-2011 04:24 PM

Re: Troubleshooting bad Half Shaft/Steering Rack/Front Bearings
 
Judging from that video, i cant tell much. It sounds like it's just catching on the gear lock, where it's supposed to catch. Is there a sound we cant hear? Can you fully lift the Jeep to allow the tires to fully rotate?

jayloop 12-22-2011 07:19 PM

Re: Troubleshooting bad Half Shaft/Steering Rack/Front Bearings
 
With the frond end off the ground, vehicle in park and e-brake applied and front wheels turning, the driveshafts don't turn, only the front axles turn. They aren't noisy. I took a video from underneath while driving. With the high wind noise picked up from the camera it is hard to tell exaclty how loud the noise is, but you can hear it.
In this video I am purposefully changing from accelerate/coast/accelerate/coast...You can hear the noise during the coast cycles.


the reason I am leaning toward the front driveshaft as the issue is that as soon as I put preload back on it by giving some gas, the noise stops. I stopped at the dealership and they said a new front driveshaft is $357 after tax with a 1 hr install at a shop rate of $100/hr.

jlewissystem 12-22-2011 07:40 PM

Re: Troubleshooting bad Half Shaft/Steering Rack/Front Bearings
 
1st off - nice vid! That's pretty sweet. COOP - under Jeep cam man, check it out! The dealer price and install isnt that terrible. BUT hearing that noise and what you describe, (to me) it could be in the front diff, driveshaft or xfer case, without being to hear specifically where in there. The acceleration pressure would keep all of those components engaged, but could all exhibit that symptom - broken tooth or what not. My lack of experience doesnt help here, but I'd almost have to open things up to look.

jayloop 12-22-2011 08:29 PM

Re: Troubleshooting bad Half Shaft/Steering Rack/Front Bearings
 
Ha! I zip tied my iPhone to the undercarriage :).

You are right, it could be in a few areas. I think I've got it narrowed down enough that I can take it to the dealership and not get fooled into it bieng something it's not. Unfortunately I just don't have the time to tear into it right now. Thanks for the input and I'll post back what the root cause was once it's fixed.

SvenskaJeepGuy 12-22-2011 08:31 PM

Re: Troubleshooting bad Half Shaft/Steering Rack/Front Bearings
 
these all match my problems right before i had to replace my drivers side half shaft

1. vehicle has to be moving
2. roaring is in harmony with RPM
3. mostly occurs when coasting downa after acceleration.
4. When close to a stop, it feels like something is grabbing the left front wheel.

jayloop 12-23-2011 08:18 AM

Re: Troubleshooting bad Half Shaft/Steering Rack/Front Bearings
 
SvenskaJeepGuy-
Thanks for letting me know that! How much did replacement cost you or did you do it yourself? At the least I'm going to drop it off at the dealership today and let them diagnose.

jlewissystem 12-23-2011 08:53 AM

Re: Troubleshooting bad Half Shaft/Steering Rack/Front Bearings
 
Good luck! Keep us posted.


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