Macster

The front diff -- like other assemblies -- can fail at any time.

Fortunately most don't fail at 42K miles.

A front diff failure at 42K miles is a *new* car problem, as the new car warranty runs 4 years/50K miles. While certainly the 4 years have elapsed for most premature failures it ain't the time that brings the failure condiiton to light but the miles.

Might add that the front diff axle flange seals were found to be leaking on my 2003 Turbo. I forget at what miles but close to if not over 100K miles and the seals were replaced the diff fluid replaced. Had the leak not been spotted the diff might have lost enough fluid to ruin it.

So while not that common the fact the front diff was repaired (probably replaced) is not a deal killer in my book as long as the front diff/axles manifest no noises and the seals show no signs of any leaks. And of course the rest of the car checks out. Don't focus on a front diff repair in the past and miss out on issues from other areas of the car.

Give the car a thorough used car check out: Test ride, then test drive, then a careful check out on the lift for any leak sign or other signs of trouble.

DaveCarrera4

My C4S diff developed a bearing noise and seal leak at 90k miles. Replaced it with a lower miles take off from a turbo, a couple hours at the local Indy. Replaced the bearing on one side and both seals and sold it on to pay for the replacement diff and install, and then some.

nbressette

Had mine fail at 55k miles, loud bearing noise that sounded like tire noise but louder.

Was rebuilt by california motorsports. labor and rebuild combined I was 4k out of pocket with vision motorsports doing the work.

"02996ttx50

i have one and its a 60lb paperweight. if i had to replace mine for 4k? and didnt live in snow drifts, i'd get rid of it go rwd, and at the very least put in a wavetrac or another lsd, and have a much more responsive car!

nbressette

Knowing then what I know now maybe I would do the same. At the time I owned the car for less than 30 days and it was my first Porsche so I wasn't brave enough to do something like convert to RWD.

I'm think in the minority in that I don't share the same disdain for AWD that others do.

"02996ttx50

perfectly understandable in your reasoning i'd say. i'm not at all sure that any "majority"? "disdains" the awd feature of the turbo? i can easily imagine it being helpful in inclement weather. but i live in a virtual desert here and the car in rwd configuration is far more enjoyable, i find. as were my all previous 911s. most understand the perceived "benefits" of one configuration over the other. depends on how the car is used, i suppose.

911mhawk

ditch the unit if you can't fix it right then claim you love rwd despite living in the rain and wanting to drive it all year....

"02996ttx50

another idea ( weather conditions permitting? ) is to simply remove the cardan shaft,.. which takes a few minutes at most.

this will disconnect the awd completely. of course then you'll be running "open diff", which is essentially 1 wheel drive lol. which also sucks! but it's a workaround for temporary day to day driving and the fried front diff will be rendered moot and non essential. now that it ( once again?! ) actually rains in SoCal! i have no issues running rwd with the wavetrac.. it's snow, or sand dunes lol.. i would be concerned with.

Macster

While disconnecting the cardan shaft means no torque is being transmitted to the front diff if the axles are still connected between the front diff and the front hubs the diff is still being used and the viscous coupling is being spun. Since the cardan shaft is not attached the discs connected to the front diff will spin the discs that would be -- if the cardan shaft present -- connected to the rear diff. These however, will turn in unison so no heat will be generated at least due to dissimilar speeds of the two sets of discs in the viscous coupling fluid.

But a "fried front diff" still has to operate as a differential dealing with speed of rotation differences between the two front wheels/tires and just removing the cardan shaft may not be sufficient if the front diff is truely "fried".

"02996ttx50

awesome! lol thanks for that! ( i think..? )

Dennis C

The front differential in my 996 C4S failed at roughly 90,000 miles. I was quoted ~$7,000 for a new differential plus labor at the dealership. I ended up having it rebuilt by a local independent Porsche mechanic for ~$3,500, all in. It took the mechanic a couple of weeks to source all the parts, but it was well worth the wait.

Kevinmacd

New replacement front diff assembly from Sunset Porsche is $5577