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Old 08-24-2012, 07:12 AM
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MCDavis
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Originally Posted by dave247
Hey guys. First post. I just got a 2004 Ford F150 Titan 5.4V8 with a little over 150k miles and I am trying to figure what the problem is with this noise I am hearing. It was from my dad who passed away, and he took pretty good care of it. Anyway I am running into a few small issues here and there and need some input.

When I am driving and come to a stop, then make a turn, I hear and feel a slightly quiet rumble noise from the rear axle that sounds like grinding or slipping. It only lasts for about one second, or for as long as I am turning. It doesn't sound horrible, but I know something is probably not right.
First off, does your truck have a limited slip differential? The axle code on the driver's door sticker would reveal this. If it's a Letter and a Number, then it's LSD. If you're only hearing the noise while turning, then the clutch pack in the diff is likely the culprit.

Originally Posted by dave247
My brother, who had the truck for a little while, informed me that it was the rear clutch pack going bad. However, he is not a mechanic and I am hoping he is wrong. A mechanic friend of mine said that the lug nuts could be loose or it could also be the wheel bearings going bad. So we jacked up one of the rear ends and I pushed and pulled my wheel and felt just a little bit of play. I then tightened my lug nuts and there was no play. However the truck still makes the noise when turning.

Is there any way I can be sure which of the two problems it is (bearing vs clutch pack)?
Tightening the lugs is always a good thing, but this is likely not the problem.


Originally Posted by dave247
Other notes:
- My ABS light flashes when I first start driving my truck and then remains on. I read in another thread that this can indicate the clutch pack problem.
- This truck recently had a front wheel bearing replaced... I assume they would have checked all the bearings though..
- A few days ago, I was driving and I heard something like metal slipping out and then I heard what sounded to be a piece of metal landing on the pavement and bouncing away... I thought "oh no..." Could that have been a wheel bearing? Hopefully it's just something I hit on the road but I doubt it.

Any help or input is very appreciated!
EDIT:What the hell is the difference between the rear clutch pack and rear wheel bearings? Aren't they in the same spot? Same thing? Similar things?..
A bad wheel bearing (located in the wheel hub) just behind and inside where the brake rotors are, will "humm" at any speed while you're cruising. Usually as speed increases so will the humm.

The clutch pack is the limited slip package that is located within the rear pumpkin (aka, differential) in the center of the rear axle.

I hope this helps.
It sounds like a bad clutch pack for sure. Adding some friction modifier can help if the pack isn't too far gone. If you have to replace, then the mechanical LSD from Eaton is not a bad replacement.