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C4 C4S question front wheels not powered?

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Saw my wife spin out on the highway today in our C4S. It was very icy. Nobody was hurt. I tried to drive it out. The front wheels did nothing. I turned the PSM on and off, did not change anything. When she came home I had her try to pull up the driveway. We have a slight incline with plenty of snow. Front wheels did nothing. The car has Blizzaks. I looked on you tube and saw Carrera 4 convertible hanging off the road with the left front wheel in the air. When he gassed it the left front started to spin. I have tried to find out how the system works. I have not seen anything definitive. I called the dealer, he said if there are not any lights on, that it is working. I am tempted to pull the cladding to see if the prior owner pulled out the drive shaft. Any ideas or info?

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The AWD does not work like what you think it should work. My

brother had the same problem as you. He tried to go

up his icey drive way and the car lost traction. It slid

backwards and damaged his tail pipe. He has

a 2006 997 4S.

Your car is a active AWD and that is the problem.

Old 4 wheel drive trucks required the driver to get out of the truck

and lock the front hubs. Then the fronts would pull and the rears would pull.

Your car has a front differential and a rear differential. There is no way to lock

the differential. One front wheel can spin and the other front wheel does nothing.

Hope this clears up your question. I am sure that everything is hooked up fine.


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C4's are AWD, and thus you actually have three diffs center (which is part of the transaxle), front and rear. However, both front and rear diffs are open (unless you have installed an LSD in there), so my guess is that one rear and one front would spin, but you're never going to get power to all 4 wheels this way if traction is an issue.

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The PTM transmission explains the difference compared with the

996 Turbo. Sounds like the Porsche Engineers solved

the problem for the 997 Turbo.

All this means is you need to buy a 997 turbo

and sell the 996 4S.


If you want more than 5-10% of the engine torque routed to the front wheels of a 996 or early 997 then the procedure is to drive agressively in a tight circle about 10 revolutions. With that much sustained disparaty between the F/R driveline rotation speed the VC will "stiffen" long enough for the average road course.

The newest 997 now has an actual functional R/awd system using the same electromechanical clutch setup Ford has used, pretty much UNSUCCESSFULLY, in the Escape and Mariner. Now in use in the new FWD or F/awd 2011 Ford Explorer (yes, that says FWD & Explorer) but with water cooling of the PTO. With the C4S being R/awd the problems Ford has had are unlikely to affect the reliability of the Porsche version.


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