2011 Cayenne Turbo Front Cardan Shaft Grease Leak / TC Questions

[tkbailey]

My recently purchased 2011 Cayenne Turbo has about 112k miles.  I'm getting some slight bucking during moderate acceleration in 2-3 gears.  Not enough the wife has noticed and I even questioned whether it was just the bumpy road, but trying different suspension settings doesn't seem to change the issue.  Also the revs sort of hang/bounce around 1800rpm.

 

Seems like it might be the transfer case.  I've read plenty on that, and decided yesterday to flush the fluid with Revenol.  The TC was replaced by a previous owner via dealership around 40k miles.

 

While under the car, I noticed the front cardan shaft (not sure if that is the right term, I haven't found much information on this part) is slinging a little grease from the bearing that is close to the TC.  I'm wondering:

 

1. I haven't read anything about these failing, and even finding a replacement part seems a bit difficult.  Places that rebuild cardan shafts don't seem to list these on their websites.

2. It looks like the shaft is about $1k, which seems crazy, and I'm wondering if the bearing can just be resealed (either DIY or shipped out).

3. If it's slinging grease out, water can get in, and the bearing might be already wearing - could this be causing the issues I'm seeing?  It's my understanding the torque split to the front wheels increases under certain situations, so more power may be diverted up front under the load I'm giving it.  But I don't know what the symptoms of this bearing failing would be, or how critical it is to address this proactively - does it fail violently, or just become increasingly annoying?

 

I asked about this on another forum and about all I got was "TC needs replaced", which seems a bit premature, since it sounds like a decent number of folks have at least temporarily resolved their issues by a fluid flush.  Might as well give it a shot, unless I totally misread everything about TC issues. 

[JE 17]

Is this actually "grease," or just seepage with attracted dirt?

I would think if the TC was replaced, you shouldn't have an issue with it. 

Also, I am not clear on where you see this. If it is from a surface on the TC, then it is a seal in the unit. There would not be a seal on the driveshaft itself. But I have mine on the lift at the moment and will try to see what you are referencing. Ok, in examining it, there are no u-joints on the driveline (-shaft, cardan) at that point. Mine is completely dry there at 90k, so if you see anything, it is from a seal on the TC.