Front Vibration during low speed turning

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JoJoDaClown

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2017 Expedition MAX 4x4. Recently, the truck has started to vibrate, but at the front end, during turning at low speed. Forward or Reverse. It feels very similar to the common rear LSD shutter that happens when you need to change fluid and LSD additive. It makes me think it's the front diff. I changed the fluid, which was very black and your shimmery, but no flakes. I plan to run this fluid for a month and go do some figure 8's in a parking lot to work it through, then change it again.

What scares me is it almost seems like something may have happened that the drive axle is no longer firmly secured to ensure proper alignment between the bevel to the pinion. Like the cap cracked. From what I can tell, though, is the front diff cover can't be removed without taking out the steering rack. Anyone tried before?

The vibration doesn't occur when at a complete stop and going knock to knock on the steering, so it doesn't appear to be rack related. No steering wheel wobble occurring either, so don't think it has anything to do with steering linkage or ball joints. Everything looks good underneath for those, too.


Does anyone else have some theories as to what it may be?
 

justinp16ex

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2017 Expedition MAX 4x4. Recently, the truck has started to vibrate, but at the front end, during turning at low speed. Forward or Reverse. It feels very similar to the common rear LSD shutter that happens when you need to change fluid and LSD additive. It makes me think it's the front diff. I changed the fluid, which was very black and your shimmery, but no flakes. I plan to run this fluid for a month and go do some figure 8's in a parking lot to work it through, then change it again.

What scares me is it almost seems like something may have happened that the drive axle is no longer firmly secured to ensure proper alignment between the bevel to the pinion. Like the cap cracked. From what I can tell, though, is the front diff cover can't be removed without taking out the steering rack. Anyone tried before?

The vibration doesn't occur when at a complete stop and going knock to knock on the steering, so it doesn't appear to be rack related. No steering wheel wobble occurring either, so don't think it has anything to do with steering linkage or ball joints. Everything looks good underneath for those, too.


Does anyone else have some theories as to what it may be?

Can be tough, I was convinced my vibration was from the front until I realized it wasn't. It was the the rear diff. Took me some messing around and listening in the driveway figure it out.
 
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JoJoDaClown

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Can be tough, I was convinced my vibration was from the front until I realized it wasn't. It was the the rear diff. Took me some messing around and listening in the driveway figure it out.

True, after your comment, I went around a bit and I guess I don't know for sure if front or rear, but it just feels like it's the front? Also, I just changed the rear last year with Amsoil Severe Gear 75w90 and the Ford CM19546A1 Friction modifier. So I'm doubting it's the rear.
 
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JoJoDaClown

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How many miles?
54,000.
Mostly no towing until last year after we bought a camper.

This past winter I got stuck and did the back and forth love making with the snow drift until I got out, in 4L.

About 1 month or so ago I had gone through with FORScan and cleared learned tables.

It started happening 2 weeks ago.
 
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LokiWolf

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Possible front Hub locked, and not disengaging.


Sent from my iPhone using Tapatalk Pro
 

justinp16ex

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Ya it's low mileage but I think it's your rear diff clutch packs. They aren't very durable, even though you've maintained it. Could try dumping some more friction modifier in. People have had these things fail with only 20k miles. Could be something else but you have the usual symptoms. Are you still under warranty?
 
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