C4S front differential leak - advice needed

I'm in the process of putting in an IMS Solution and spent a little time today tracking down the source of a small oil leak. The spot is appearing on the floor on the driver's side of the car, about 3/4 of the way up. I'm assuming the underbody covers were channeling the leak away from its source, but after looking at things I believe its the front diff leaking. I've attached pictures - leaking appears to be happening on both sides and possible at the back where the drive shaft hooks up. If someone that has dealt with this before and can confirm what the leak is caused by and best course of action, I would really appreciate it. I have the transmission out of the car now. If the seals need to be replaced, would it be easier to just pull the diff since I have the transmission out or replace them with it in the car? One other thing to note - I just bought the car from a Porsche dealer and have a 1,000 mile power train warranty. There are currently 13 miles left on the warranty. How much of a pain, or how potentially big of a problem is this? I could probably call them and have them pay for new seals - but if this is potentially something more serious it might make sense to put the transmission back in and take it to a dealer for repair. Thanks in advance! Charlie

Leaking is the first sign of failure in your front differential. I suggest that you replace the seals and bearings before they fail, or you could face an expensive repair bill.

Take it out!

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Have the dealer fix it under warranty. Than take it out.

The front diff axle flange seals on my 2003 Turbo leaked. Tech replaced them. I forget the exact cost but figure 3 hours labor and incidentals and you could be looking at a $750 (or higher) repair at a dealer. With the warranty I'd have the dealer replace these.

Definitely have the dealer replace at their cost. . . or you could always buy my 2WD conversion.

Thanks for the input everyone. I contacted the dealer and it seems I misunderstood how the warranty I purchased worked. Apparently it only applies to mechanical failure and not leaks. To be honest, I do remember them saying something to that effect early in the discussions - although the actual warranty paper isn't very specific and does list leaks on the back but doesn't say if they're covered. Regardless the true reason I purchased the warranty was to cover the 1,000 mile drive home in case of IMS bearing or other major failure. I made it without issue so I am content saying I got my $ worth and purchasing/replacing the seals myself.

As far as the warranty - that is a chicken sh*t answer. The reason it's leaking is that a seal failed or is failing - so there is a part that needs to be replaced. You can't service this unit yourself (you could top up the engine oil if it were losing a few drops, but how do you do this with the front diff?) - and depending on how much lubricant is gone, damage may already have been done. I would push for the repair, but if they won't budge - and you don't use this as a winter driver - lose the front wheel drive stuff. The car will be lighter and more fun to drive. *edit* Ah, you're the DIY Solution guy. You might post up in the parts wanted section and see if anyone near you has done the FWD delete and would be willing to part with their diff. Mine is hanging from the rafters in my garage, but I imagine it would cost several hundred bucks to ship to OH.

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I agree, but to be fair the warranty also states work has to be performed on premise. It's a lose/lose scenario for both sides. If I needed a new engine it would be a different story, but for a relatively inexpensive seal that I should be able to do myself I'd rather cut losses and get the car back on the road. Regarding everyone's comments about ditching the AWD, I'm a little surprised. I definitely appreciate rear wheel and the additional fun of loosening up the rear end under hard acceleration and around corners - but without a limited slip in the back aren't you either getting interference from the braking system that prevents slipping? My Z4 is RWD with no LSD. With the electronic auto slip reduction (or whatever its called) it just feels awkward and annoying trying to slide around a corner, and with it disabled it still feels a bit awkward with only one wheel in the rear losing traction. Maybe its different in a 996? My 94 RX-7 had a torsen limited slip and absolutely no traction aides of any kind - it was a bit precarious and not very predictable for any type of power sliding but when accelerating hard it felt great because the rear end would wag as both tires fought for traction.

When the front differential failed in my 996 C4S, it began with a small leak. That was quickly followed by noise from the front end. I investigated the potential courses of action (I wanted to keep the AWD system) and I came up with the following options: 1. Replace the front differential with a new OE part. This is the option typically recommended by dealers. The part alone is approximately $7,000, so this isn't a cheap option. 2. Install a used or rebuilt differential as 5SCHN3LL suggested. Some Porsche parts resellers will sell a used front differential with a warranty, usually no more than one year. 3. Have your existing differential rebuilt. This was the option that I chose. It was a little over $3,000 as I recall, including parts and labor. It was like new again when it was finished. When my original differential was disassembled, one of the ball bearing cages had broken open and there were loose ball bearings in the case.

As far as deleting the front-wheel drive components - it does not cause any issues with PSM. PSM operates on wheel slippage and is in no way tied to the transmission. PSM does not know anything about power going to the front diff; I haven't noticed ANY difference with PSM since I removed the FWD stuff two or three years ago. When I removed the front differential, I disassembled the half shaft joints and kept the original axle stubs to ensure that ABS and PSM continue to work as expected. Porsche sold a ton of RWD 996's; they definitely didn't feel like the car NEEDED 4WD to be safe to drive. While it is conceivably easier to break the rear end loose, it just doesn't happen unless you want it to. The "snap oversteer monster" of the 70's and 80's 911 was stomped almost completely out with the 996's geometry changes. The viscous coupling isn't necessarily instantaneous - that one time a day when you nail it around a corner and the inside rear tire starts to break free - but then gets reined in by PSM retarding the timing - is going to happen whether or not you have the front wheel drive components. If you are trying to get up an icy 10-percent grade driveway or street, I'd urge you to leave the front wheel drive components in place. I do a decent amount of alpine driving in my 996, and I can say with absolute certainty that I like my car better WITHOUT the AWD system in place. I do most of my uphill mountain driving with PSM disabled.