Well, with 12" of snow in Charlotte I decided to prove my wife wrong and take the 996TT to get pizza.

10 feet after leaving my driveway, STUCK. Needless to say she was not pleased at having to help me tow the TT back into the driveway. All while reminding me we have a Land Cruiser for this kind of weather and that I am an idiot for even trying.

BUT - while my neighbor was watching me spin the tires trying to make it up our driveway...... he commented that the fronts were not spinning at all while the rears were slowly spinning (3K in 1st)

SO - is this a clear sign the front diff is gone? Or, is there an easy way to test? Usuallly I can feel the front pulling from the fronts in high speed sweepers on the track but maybe I am imagining that..

Any help would be appreciated. BTW 25K miles. Slightly modded ECU at 17K miles and 2K miles of track time.

 

Was wondering if you tried it with the "PSM" in the off position and would low hydraulic fluid would cause that to happen? Hope it's not serious.

 

Try jacking up one front wheel off the ground. You should be able to slowly turn it against the central differential's drag.
You should have been spinning one of the front wheels.

 

Thanks for the replies...

PSM was off, I thought a bit of spinning may be better to get thru the snow.

I will try it with the car on a post lift.

Thx

 

Correct me if I'm wrong, but I thought the front wheels aren't activated until the car reaches 30-40 MPH? Anyone else know for sure?

 

It is a simple viscous coupling. The torque to the front wheels increases with the speed difference between the front and rear. I don't think there is any centrifugal action that increases lockup at higher vehicle speeds.

 

Here's my theory; Highly unlikely your center diff has failed unless you did something pretty obvious to cause that to happen. So here's my guess - probably when you switch off PSM, you're also switching off the limited-slip functionality of the rear diff (the TT does not have a LSD, instead it uses PSM to limit slip). Your neighbor's side rear wheel was spinning, but how about the other side? I'm assuming that unless both rear wheels are spinning, the center diff gets no input - therefore no power to the front. Of course if you believe that both your rears were spinning, then my theory is shot to hell.