Replacing front differential on C4S

My car was making a noise in the front. Shop said front differential. That and some other stuff, 8k. The shop is really good. Can the front differential be disconnected just to buy my self some time? I don�t want to drive if safety issue. 2002 C4s Thanks, David

I purchased a used front diff from a 996tt owner who did AWD to RWD conversion for $300. Labor cost to swap them out was another $700-$800 I believe.

Quotes source post: 18061280

kind of but it takes a lot of work. You can drop the drive shaft, but the diff will still be spinning from the front wheel hubs. They do make kits to swap the axle shafts for axle stubs to eliminate it completely. Look up awd to 2wd conversion on the 996tt forum and you should find all the info you need.

What are the signs of a bad differential? The shop said it was my problem but I am just not so sure. The noise is very intermittent. it seems to be coming from the left side, not the middle. it�s a clunk noise. No whining noise. Occurs with left side bumps and when starting off stop to go and again, less likely not to occur. Thoughts?

I suppose you could remove the prop shaft and front axles as a temporary measure? Is everything tight?

Klunks can be anything from worn CV joints to worn ball joints, worn strut mounts, worn control arms, or any other suspension bushing. A differential would only klunk if it has lost all of it's preload which would only happen if it is completely worn out. I doubt that the differential is the cause of the klunk. The rubber mounts for the differential could be klunking though. I would get a second opinion.

The shop told me I can still drive and I�m at the very early stages of failure. It will give much bigger signs when failure is eminent. Does my symptoms sound like a bad Dif? There is no strange noises when driving just occasionally at launch or a bump. Like something is shifting.

My front diff made a constant whining sound when off throttle and was leaking a little fluid which permanently stained my driver's side front rim. There were no clunks or similar noises. Could those be motor mount related? Just throwing out an idea.

@Argeo where are you located?

Scituate, MA It�s not so much the money though it�s a lot. It�s that I�m not sure it�s the problem and I feel like the 13 hours are excessive. Looking at my resources, it doesn�t really look that bad with a lift and someone familiar with cars and instructions. A new dif is approx 3-5k. Though not new, a refurb�d one is 1.5k.

I need to go find my invoice for my Diff swap but off the top of my head I think I was charged for 9 hours. With all the 996tt owners who do AWD to RWD conversions I see no reason to buy a new one or even a refurbished one. Just find a low mileage one that was removed and check the seals for any leakage. There must be other shops in your area to get 2nd opinion from as well.

Almost certainly not the differential. There's something else in the suspension that is worn out.

That doesn't sound like a differential. Also, did I read correctly they quoted you 13 hours for the job? It's a 2-3 hour job if you take your time and go slow with the car on jackstands, it's actually a very DIY-friendly job. Your symptoms don't sound like a bad differential, it sounds more like a bad CV joint to me, or something in the suspension.

Im putting my money on a blown upper strut mount.

Not saying it isn�t but it�s new and I�m pretty sure the noise was there before. Drop Link? Certainly the easiest first step.

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Did not know it was new, make sure the top nut is tight. Sway bar link is a good guess too.

Quotes source post: 18061280

Do you actually need AWD? A lot of people spend money to do the 2wd conversion when their differential is fine with the goal of improving the driving feel. With the 911's engine (weight) over the rear wheels, AWD isn't strictly necessary even in snow (with proper tires). Maybe drive a 2wd 996 and see if you prefer it before making the decision. I know I definitely prefer my current 2000 2wd over the 2001 Carrera 4 I had back in the early 2000's. Are tire diameters and tire inflation correct? I think performance of the awd is very sensitive to those factors.

When I can was searching for a 996 I drove both 2wd and awd and preferred the feel of the awd. It felt more planted and I�m not tooling around and skilled enough to work a rwd car. Also, I think when I sell; having as it left the factory will help the price. Silly but that�s what seems to happen. Not selling soon. Thanks, I�ll start with link.

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You mean some people actually want awd ? What a novel idea� I thought EVERYONE removed the front diff�