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Porsche mechanic told me the reason they don't put PDK in Cayenne's is the transmission can't take the extra weight, even without towing a trailer. Maybe the Mecan is too heavy for the PDK as well. Maybe Porsche are working on beefing the PDK up for their SUV's?

Machog
 

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I was thinking it might be interesting to know the % chance of a Porsche PDK failure versus a MT failure (I recall that not unheard-of) but I suspect it would make little difference to someone choosing one over the other unless the difference is extreme.
MT is a wear item. Its guaranteed to wear out, and subsequently fail. Its just a matter of when. Not sure if you mean something other than normal wear.

Even if the rates of failure are about the same, isn't the difference in downside cost 'extreme'?
I believe PDK was meant to be a lifetime unit. Even so, does that mean all 100% of the units never fail? I doubt that. I'll guess they expect a certain percentage of failures. If its out of warranty, well thats the price of doing business. You pay $18K or so and some people appear to be doing so now. There are clutches in there. Parts fail. Maybe they don't expect people to own PDK cars for 15 years? I don't know. But with MT, you know.

Porsche mechanic told me the reason they don't put PDK in Cayenne's is the transmission can't take the extra weight, even without towing a trailer. Maybe the Mecan is too heavy for the PDK as well. Maybe Porsche are working on beefing the PDK up for their SUV's?
First sentence is true. PDK not intended for the full size 4 x 4. Second part is a different issue. The Macan PDK is not the 981/991 ZF PDK its a Audi DL501 DSG modified by Porsche for the CUV. It has, allegedly a definitive torque limit, just like the sports cars. People are now starting to "tune" the twin turbos and I guess its a matter of time, maybe years, we start seeing failures. Of course, that's on the owners. I think their claims will not be honored on warranty. You break it, you pay for it. OTH, the early Macan PDK failures look just like what it is - failures of the unit. Early adopters have issues. Its all under warranty. Maybe they rushed this out to fast. But then again, you got to look at actually numbers. I dunno how many Macans have failed worldwide compared to total production? Someone would have to run the numbers. Lots of people need post anything in forums so who knows the true numbers. IMO, early Macan failures are just early adopters runs into issues.
 

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Even if the rates of failure are about the same, isn't the difference in downside cost 'extreme'?
After my experience with the sun visor clip, I'm ready to concede that in terms of cost, a dome-light failure on a Porsche is "extreme". What I was meaning is the delta in failure rates, would it affect decision making? If, say, if you bought MT you had a 2% chance of a transmission failure in the first 100K miles, and with a PDK it's 27%? I still think people would choose the trans they wanted except in a few on-the-fence cases.
 
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After my experience with the sun visor clip, I'm ready to concede that in terms of cost, a dome-light failure on a Porsche is "extreme". What I was meaning is the delta in failure rates, would it affect decision making? If, say, if you bought MT you had a 2% chance of a transmission failure in the first 100K miles, and with a PDK it's 27%? I still think people would choose the trans they wanted except in a few on-the-fence cases.
I don't know how other people would necessarily do things, hence my question.
But 27% failure in the first 100K miles probably means many are post-warranty in these cars. While that might not affect short term original owners, it would probably affect resale and deter some long term owners (like me).
(It would probably also mean lots of angry posts on websites like this one. ;) )
 

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Porsche mechanic told me the reason they don't put PDK in Cayenne's is the transmission can't take the extra weight, even without towing a trailer. Maybe the Mecan is too heavy for the PDK as well. Maybe Porsche are working on beefing the PDK up for their SUV's?

Machog
With regards to the Macan and PDK, I hoipe that you are wrong, but the worry of it all has me thinking about an extended warranty!
 

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After my experience with the sun visor clip, I'm ready to concede that in terms of cost, a dome-light failure on a Porsche is "extreme". What I was meaning is the delta in failure rates, would it affect decision making? If, say, if you bought MT you had a 2% chance of a transmission failure in the first 100K miles, and with a PDK it's 27%? I still think people would choose the trans they wanted except in a few on-the-fence cases.
I'm one of the on-the-fence guys with respect to PDK, but if the known failure rates with a manual (requiring transmission replacement, not just clutch) were 2 percent, and the failure rates for PDK (which is almost always a full gearbox replacement, even for something minor) were 4%...I'd NEVER opt for PDK. Of course, with the Macan and the Panamera there's no choice, and the only manuals I've ever seen in Cayennes were in the base and the diesel. With a 718 or a 911, I'm biased towards manual...but even a 10% or 15% KNOWN increase in PDK failures would see me choosing manual. Trouble is, we have no way of knowing what the failure rates are for either transmission choice.
 

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The problem with PDK and SUVs are that the clutch packs have to be bigger to handle the loads. Likely every other part, too, and the weight becomes prohibitive. At some point, the weight and fluid pumping losses to cool and drive the clutch engagement/disengagement outweigh any gains from a dual clutch design. The main difference in efficiency is that the pumps work harder the faster the engine turns. This adds an RPM-dependent factor to the efficiency. At 8000 RPM, a 981 PDK requires 5 percent (over MT) in losses to pump the FFL-3 fluid in the clutch. Since the car runs under 2K RPM most of the time, the losses for highway efficiency are minimal.

Now I am sure you have heard by now that at least 50 MT GT4s around the world have lost 3rd gear. Porsche has replaced them, but at least for one car, the replacement failed in the same manner, necessitating a second replacement. Supposedly early production GT4s are unaffected as at the middle of GT4 production, Getraq changed the way they made 3rd gear and the new design did not hold up.

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Or, one failed and was replaced...then the replacement failed.
Third time is a charm!?

Kinda scary, at least in a Macan they don't charge you $4000 at time of purchase to get the party started.... one of the other reasons I only considered a MT for my BGTS!
 

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Last evening....was in automatic mode - 5th gear...30 mph....suddenly heard an awful clunking sound.
got this diagnostic: "Transm. fault Poss. no R gear Drive on poss."
Car now towed to my local shop.
Only 15k miles on the tranny !!
Doubtful my car's condition is this (from a previous post): "it is just a sensor misread. It never happened again."

So much for the local dealer saying "we rarely have PDK failures".....LOL.
 

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MT is a wear item. Its guaranteed to wear out, and subsequently fail. Its just a matter of when.
A Manual Transmission RARELY wears out. The clutch is the only wear item. The bearings, synchros and gears themselves will last a million miles or more unless they are abused.

I believe PDK was meant to be a lifetime unit. There are clutches in there. Parts fail. Maybe they don't expect people to own PDK cars for 15 years? I don't know.
You are contradicting yourself....PDK's have electronic servos and switches that have a very limited life expectancy relative to the life expectancy of a gear or bearing. The clutch packs are not necessarily any more durable than the clutch used in a manual transmission, so if you claim that a Manual Transission is guaranteed to wear out, how can you claim a PDK is meant to be a lifetime unit???
The biggest issue with a PDK is that it is not mostly repairable. It is too complex and when almost any major part breaks, you are forced to buy a remanufactured or new PDK. I know of R-8 owners paying $30K for out of warranty PDK failures. An Automatic Transmission could have/ would have been repaired, a Manual Transmission, could have/ would have been repaired, but being a PDK, they claimed that they cannot properly repair them and the factory forces you to pay.
 

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A Manual Transmission RARELY wears out. The clutch is the only wear item. The bearings, synchros and gears themselves will last a million miles or more unless they are abused.

You are contradicting yourself....PDK's have electronic servos and switches that have a very limited life expectancy relative to the life expectancy of a gear or bearing. The clutch packs are not necessarily any more durable than the clutch used in a manual transmission, so if you claim that a Manual Transission is guaranteed to wear out, how can you claim a PDK is meant to be a lifetime unit???
The biggest issue with a PDK is that it is not mostly repairable. It is too complex and when almost any major part breaks, you are forced to buy a remanufactured or new PDK. I know of R-8 owners paying $30K for out of warranty PDK failures. An Automatic Transmission could have/ would have been repaired, a Manual Transmission, could have/ would have been repaired, but being a PDK, they claimed that they cannot properly repair them and the factory forces you to pay.
i would have thought like the engine, the gearbox is a long life part (lifetime is an unhelpful term with 1970 and earlier cars still running with re-built engines and gearboxes). A manual gearbox's clutch is a consumable item whereas the integrated PDK clutches (it's a dual clutch system) are designed for long life and presumably why they are a wet clutch design.

It seems to me that there are few ZF PDK failures just as there are few manual gearbox failures.
 

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A manual gearbox's clutch is a consumable item whereas the integrated PDK clutches (it's a dual clutch system) are designed for long life and presumably why they are a wet clutch design..
A wet clutch is still a wear item. Look at motorcycle wet clutches, they wear out as fast as your Porsche clutch.
The reason a PDK clutch should last longer than your 3rd pedal clutch is the time required for complete engagement is measured in hundreds of a second in a PDK ( coupled with ultra precise rev matching) instead of tenths or longer with a 3rd pedal car. Few drivers can properly operate a clutch. Even fewer can maximize clutch life by proper rev matching with heal toe shifting. Proper heal toe shifting results in less clutch wear even though the clutch is actuated twice in each shift. No human can match a PDK for it's ability to rev match and no human could release and fully engage a clutch as quickly as the electronic servos in the PDK.

Very few realize that the computer reduces engine speed during every upshift even though the driver hasn't change the right pedal position. Drive by wire throttles have eliminated most of the driver's control of the throttle. You push the right pedal then the computer decides whether or not to open the throttle and how much to open it. The computer also blips the throttle on every downshift even though, once again, the "driver" hasn't moved his/her right foot.

The only reason people think that a PDK might last a lifetime is that they think it is an automatic transmission (which also has clutch packs). They really don't understand the differences in design and operation. The clutches in both a PDK and an automatic transmission will wear out eventually.
 
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