2012 Titanium Front Strut Low Speed Noise (Clunk/Rattle)

[thejordan]

Originally Posted by revhigh

Zillion is 100% correct ... otherwise it would rip the halfshaft out of the trans as it moved up and down with the bumps in the road.

Every halfshaft I've ever seen has that lateral play.

REV

Lateral play when you pull on the wheel? I still don't think so. Maybe if you disconnect it from the hub assembly and get the play, but not while everything is attached. The wheel shouldn't move.

[revhigh]

Originally Posted by thejordan

Lateral play when you pull on the wheel? I still don't think so. Maybe if you disconnect it from the hub assembly and get the play, but not while everything is attached. The wheel shouldn't move.

If the car were suspended on a lift with the wheels free, you can generally get some lateral play by grasping the halfshaft and moving it in and out of the trans slightly. Never seen one NOT like that.

OR ... if you move the wheel up and down while it's on a lift, you'll see the halfshaft move in and out of the trans slightly. IT has to be like that ... if there were no play, up and down movement of the wheel on the road would pull it out of the transmission.

If you've ever replaced a half shaft ... you'd see what I mean. There is play in the splined area BEFORE it hits the retaining ring.

REV

[thejordan]

Originally Posted by revhigh

If the car were suspended on a lift with the wheels free, you can generally get some lateral play by grasping the halfshaft and moving it in and out of the trans slightly. Never seen one NOT like that.

OR ... if you move the wheel up and down while it's on a lift, you'll see the halfshaft move in and out of the trans slightly. IT has to be like that ... if there were no play, up and down movement of the wheel on the road would pull it out of the transmission.

If you've ever replaced a half shaft ... you'd see what I mean. There is play in the splined area BEFORE it hits the retaining ring.

REV

I've only replaced axles on AWD vehicles, and I understand everything up until you pull the wheel laterally (not up/down). When the wheel is attached, the wheel itself should not be moving laterally (outwards/inwards). Unless there's some difference in design that I am not aware of...

Like I said, I'm speculating based on my experience (not with a 2012 Focus). There has to be some sort of difference between '12 axles and '13 axles since they're different part numbers from different build dates.

[jsr72]

Wheel end motion is accommodated by plunge within the inner cv joints. The halfshaft can slide laterally inside this joint housing. It can also articulate in angle.

This is needed for steering because the outer cv joint center isn't completely coincident with the steer axis. It is also needed for suspension travel because the arc of the wheel end motion isn't centered on the inner cv joint center. It is also needed to accommodate movement of the powertrain on its mounts.

[thejordan]

Originally Posted by jsr72

Wheel end motion is accommodated by plunge within the inner cv joints. The halfshaft can slide laterally inside this joint housing. It can also articulate in angle.

This is needed for steering because the outer cv joint center isn't completely coincident with the steer axis. It is also needed for suspension travel because the arc of the wheel end motion isn't centered on the inner cv joint center. It is also needed to accommodate movement of the powertrain on its mounts.

Okay that makes sense if the CV joint is allowing for this change at the wheel.

So the CV could be a likely candidate for the clunking sound? I'm wondering if the CV part of the axle is what they changed from '12 to '13 resulting in different part numbers then.

I'd like to see someone put in a '13 axle in their clunking '12.

[Shade-010]

Originally Posted by thejordan

Okay that makes sense if the CV joint is allowing for this change at the wheel.

So the CV could be a likely candidate for the clunking sound? I'm wondering if the CV part of the axle is what they changed from '12 to '13 resulting in different part numbers then.

I'd like to see someone put in a '13 axle in their clunking '12.

Sounds like something to try, couldn't hurt

[thejordan]

Originally Posted by Shade-010

Sounds like something to try, couldn't hurt

aside from the strut tower plates, what other differences are there besides the cv/axle assembly for '12 and '13? just looking systematically...

the fact that it is temperature related (grease in the CV?) and occurs on bumps like a driveway (axle?), it seems plausible. it's just a $200+ part. unless ford can explain why the axles were updated...

[Lipshurt]

Just to even clearer....

The sound my half shaft makes is when you are under the car, with it sitting on ramps, on the wheels, and you grab the half shaft with your hand and jiggle towards the wheel and towards the tranny. It moves about .030 and makes the same type of sound I hear when I hit tiny bumps, and that sound goes away when it gets hot, but it takes longer than you think. Like ten minutes, and if its colder than 45 it takes a really long time to go away, but the only time I ever had it down to 35 degrees it was silent too, and then started making the noise again at 45 degrees.

The way I understand CV joints the slack should be taken up within the parts that slide around each other, and there would be no clunking when the half shaft moved only a little bit. It's hitting something at each end of that 1/32 inch of travel.

When the suspension compresses, it would change the distance between the wheel and the tranny but way more than that, and that distance is accommodated by the CV joint. But I would think that accommodation would be silent cuz nothing hits anything.

[Dysan911]

Despite the noise from the half shaft. I mean even though it sounds similar to the clunk. The fact remains IMHO, that my dealership temporarily fixed my issue 100% for the brief 10k miles before the noise came back. As far as I know they did not replace anything to do with the half shafts, CV joints, etc. Only the Springs, Bearings, Top plate, bolts, etc. So I think were barking up the wrong tree by considering its CV/Shaft related. Obviously the noise has to be related to one of the parts replaced.

Has anyone had a close look at the dust boot on the strut? Is it pretty soft material or thick plastic that could be binding up? I recall in this thread that someone once applied a Bunch of Lithium grease somewhere on the dust boot (maybe up top) and it resolved the clunk until the grease dried up. Hmmmmm

[Dysan911]

FOUND IT!!!!!!!!!!!!!!!!

I am going to make a video and post shortly. with the help of my son I was able to reproduce the sound 100%.