I have a 2002 F150 Supercrew. Last week I was having some suspension problems on the front drivers side, so I replaced the sway bar end link, upper control arm, and CV shaft. I noticed immediately a rubbing/grinding sound in the front end.
After doing some digging last night, I discovered that the front differential is slipping. If I turn the tire by hand, sometimes it's fine, but if I put pressure on either side of the tire while rotating it, I can get the differential to slip.
Could I have installed something incorrectly or done something during the install to cause this?

Seems pretty coincidental that it would go just after I installed a new CV shaft.

 

Maybe the splines on the CV shaft and/or member of sheared?

 

The noise has to be something you did.
As for the slipping, your a bit mixed up about the front drive line.

One side is a CV axle link from Hub to the front differential.
The other side is a Vacuum actuator controlled sliding 'spline' operated in 4wd only that make the CV link solid for 4 wd.

In 2wd the front acts as an open differential not being driven by the front drive shaft out of the transmission rear case.
It has to stay open in 2wd or steering becomes difficult in turns.
.
I'm not following what you mean by 'slipping'.

.
The front wheel Hubs ride on Bearing Packs held to the spindle by 4 bolts.

If a bearing is worn, the disc will change position in relation to the Calipers. They should not move laterally, only for rotation.

If the dust shield is bent inward it might be rubbing on the disc if the bearing pack is worn.
You just have to observe for these things.
Good luck.

 

It's supposed to slip in 2wd.

 

Thanks for the replies.
Sorry, I should have been more clear. The reason I said that it's slipping is because, when I turn the hub by hand (truck jack up, tire off, brake pads removed) it's a little difficult to turn, but I can turn it by hand. If I start to wiggle the hub back and forth, I can get the differential (I have clear view to it, so I know that's where the sound is coming from) to "slip" (it starts turning freely with no resistance) but then it starts clicking like a playing card in a bicycle tire, and it will keep making that clicking sound while I turn the hub.
If I quickly turn it the opposite direction I can feel it "pop" back into place, and then the resistance is back and it's harder to turn, but the clicking stops.
I'm guessing the clicking sound is the differential gear teeth slipping over each other.

 

A little more information on the truck, I have the on-the-fly 4WD, and no locking hubs.
My 4WD switch is not engaged, but I have read that the 4WD can get stuck partially engaged, but I'm not sure how I would have done that simply changing out the CV shaft.

 

Sounds like you have some additional problem by coincidence.
Since the CV axle bolts on to flat plates on the differential outboard matching plates.
The drive plates are splined and held in by C clips same as a rear axle. That is all that holds them in.

Good luck.

 

So, you don't think that it could just be the 4WD partially engaged?

 

No I do not.
The system operation is quite complex to ever be in partial engagement.

All the functions have to be engaged from the trans to the front axles.

1. Dash switch to 4H.

2. Case motor moves to position 1, engages front drive shaft.

3. Fire wall solenoid applies vacuum to front Actuator.

4. Spline coupling locks both halves of the passenger side CV.

5. Motor has to be running to provide Vacuum.
If there is a 4wd issue, you would see it from 4wd not working. No dash lamp, no drive etc.
You can't cause a partial just working on it setting still with engine off.
Take the cover off the Actuator and check the Arm. Is it released or operated?
Still think it's partially engaged?

 

Also, you can't be serious with the statement......maybe the gear teeth are jumping over each other.
You would really have big trouble if that were happening.
That kind of happening would likely break the case.

 

This is the sound I was experiencing, and what I imagine is happening. But maybe the Ford setup is different. This is a new area for me.

 

OK, so I took a video of my truck. It's not great quality, but hopefully it will give you a better idea of what's going on.
I'm just turning the hub by hand. When the clicking starts it gets much easier to turn (not sure if you can tell from the video).

 

Any ideas on what's causing this? I was supposed to be taking this truck on a 3 hour trip tomorrow, but I'm not comfortable driving it the way that it is right now.

 

im tempted to ask:
is it possible this truck has had an automatic locker installed in the front diff at any point in the past?
probably a stupid question to some- but i just have to ask -

 

The bigger problem as I see it now is you still want some one to tell you what's wrong instead of learning the mechanics of what your trying to deal with.
Until you do it won't get any better.

Trying to explain this complexity through this medium and have understanding is very difficult.

You still have to act on the situation.
************************************************** *************************
FROM differential toward the wheel:

The small axle with the large mounting flange has a spline that engages the differential the same way the rear end axle does. Question is, is this axle loose and moving in and out? If yes the C Clip has come off.
If NO the locking sleeve on the passenger side housing is what you might be hearing.
That suggest the Actuator arm or a fault is present.
You must get this all checked out and find the cause rather than keep asking the forum what's wrong.
Do the work.
I'm sorry if it insults you but going at it the way you have so far is not solving your problem.
Good luck.