2004 cayenne , seems front diff is shot

[titan154]

was driving the other day and heard a noise , it got louder over the next 5-6 kms , then really loud like  a wheel bearing gone in front end , it seems like the front diff is gone , is this common ? and can i disconnect the front drive like have done on atv's and make it rear wheel only too save $$$ on an 04 model or will it mess the computer up because all wheel drive ? thanks for any ideas . 

[clarksongli]

I would say it's not a common problem, but you see it more and more these days. 

 

The most common failure is the pinion/or output bearings loosening up, which cause the gear mesh to get a little funky.

The other failure that I have seen (including mine) is the pinion preload get's sloppy, causing the pinion gear to slide in and out depending on the load.  Again it basically will mangle the gears up.

 

The positive side (if there can be one) is that you will basically just keep driving it.  Now if you JUST started noticing it, I would drain the fluid and see if there is metal in it.  If it's shiny, you've already started the killing process.  If not, I'd consider pulling the front axle out and seeing if I could find a bearing set to replace whatever is worn.  For me, it was already too late.  I've been driving on it for maybe 80k miles.  Is it annoying?  Yes.  But for a few thousand dollars for a core exchange, i'll just live with the noise.

 

I wouldn't bother disconnecting the axle.  Computer wise it won't know the difference (except if you are slipping the wheel) I don't think. since the wheel sensors are the only thing providing feedback for the front.

 

I'm not 100% sure which axle you have, but Timken does make replacement bearings for nearly all of them:

LM503349 bearing cost: approx. $19-$30 retail
Timken LM503349 Differential Bearing | Auto Parts Warehouse
LM503310 seat/race cost: approx. $10-$15 retail
Timken LM503310 Bearing Race | Auto Parts Warehouse
These parts are relatively common and available through multiple distributors/dealers/auto parts stores.
 

[titan154]

well today the front casing broke wide open ... oil al over the ground , so was definatly in there ,