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-   -   normal pdk slippage (https://rennlist.com/forums/997-forum/929731-normal-pdk-slippage.html)

dgjks6 04-18-2016 09:06 AM

normal pdk slippage
 
2009 Carrera 4 Cab with 8200 miles and PDK (and CPO - thank god, so none of the weird noises, smells, issues start the paranoia like I had when I owned my 996)

So when I drive off in first or reverse slowly it feels like - and I don't know how else to describe it - a newbie learning to drive a stick. If I'm on a hill I will roll backwards before going forward.

Is this normal? I did a quick search and found that others have had this issue, but I could not find any follow up.

ltcjmramos 04-18-2016 11:32 AM

May be different for a 2012, but I have to be careful when reversing. It does not do that smoothly. As you describe, almost like the tranny is slipping. More gas gets it moving, but that's where caution comes in.

Mine holds fine on slight inclines. Can't say I've paid much attention on stops on steeper hills. In another thread, it was asked whether the PDK goes into neutral at stops, mine does not. On flat ground, if I take my foot off the brake, it'll crawl forward. Hence, the hold on an incline. Take off in first is smooth.

stevepow 04-18-2016 12:33 PM

It should not roll back on hills - in fact, there's a "feature" that makes it "stick" on a hill and takes more throttle to move the car - and yes, this takes finesse or the car will suddenly break free and lunge forward. This is on both Manual and PDK 997.2 cars. Check the manual for Drive-off Assistant to see how to use it best.

Also, I find that especially when cold, I have to give a good pause after backing out of the garage and putting it in drive before pulling forward or it won't be smooth.

Nice car you have there!

TM_Corey 04-18-2016 01:46 PM

Mine also hesitates. Even from park to drive then taking off it sometimes hesitates and "bumps". First time I thought I ran something over.

vbb 04-18-2016 03:58 PM

From what I have gathered, this is just one of the characteristics of the 997.2 PDK transmission.

The horror stories of PDK failure and how they can't be repaired, only replaced, are definitely attention grabbers. Unfortunately I did not know this until AFTER I purchased my car, and no, I do not have it under warranty anymore, so again, this has made me hyper-sensitive to any perceived "issues" with my car.

I have found that while it certainly doesn't behave like a full on manual transmission, it also doesn't behave like any other auto transmission I've ever driven. I have not noticed the rolling back while on a hill thing that you've mentioned, but I have noticed that little bit of hesitation, or slipping, when taking off from 1st or reverse right after starting the car, almost as if I was a newbie driving a stick and not sure of where the engagement point of the clutch was. Almost like a bit of a rev and then the "ahh, there it is" sensation. The first time this happened it scared the crap out of me because I was sure it was some early sign of PDK failure... but I believe it is just sort of the way it operates at times. When I'm taking off in the morning or after the car has been parked for awhile, I put it in gear, lift my foot from the brake and let the car engage on its own before giving it gas. That keeps me from feeling the little bit of hesitation.

As I have an '09, I just had the recommended PDK service performed about 2 months ago. The service mechanic said the car was running beautifully, and yes, it still does the hesitation move sometimes right after I've started it and put it in to gear.

ADias 04-18-2016 04:59 PM


Originally Posted by vbb (Post 13209796)
... The horror stories of PDK failure and how they can't be repaired, only replaced, are definitely attention grabbers...

Right! And this thread's title is just a 'sensationalist' continuation of that. The OP could simply have asked a question, but he chose to affirm - pdk slipping! to end up not being that...

BTW... all transmissions must slip, that's what clutches do, albeit in a controlled way, when they engage.

j997tt 04-18-2016 07:13 PM

FWIW my 12 GTS PDK behaves almost identically to my previous 15 M4 DCT when cold and going into reverse or drive. Some slippage, not smooth until warm... I will say that the BMW unit was lightning fast when warm and in S+ mode. Seems a tad better than my 997 but is a different marque and newer box...

dgjks6 04-18-2016 07:48 PM


Originally Posted by ADias (Post 13210002)
Right! And this thread's title is just a 'sensationalist' continuation of that. The OP could simply have asked a question, but he chose to affirm - pdk slipping! to end up not being that...

BTW... all transmissions must slip, that's what clutches do, albeit in a controlled way, when they engage.

Ouch. Didn't mean to upset anyone. Just curious because I have a PDK in a 2016 Macan and it behaves nothing like the PDK in my 911.

And I tested the roll back and you guys are right. Does not roll back on hills, just hesitates a little before going forward.

As far as comparison to the Macan S. There is no slippage at all. It behaves much more like a traditional auto transmission - except for the smooth and lightning fast shifts.

And I thought it was all in my head but my wife can tell the difference between the two.

And I fixed the title for you

ADias 04-18-2016 07:57 PM


Originally Posted by dgjks6 (Post 13210508)
...

And I fixed the title for you

Nah! The slippage is not any different than in your Macan. Actually, the Macan may have a longer slip and that is why you do not feel it.

There have been several PDK software updates since its launch on the 997.2 in 2008. Some (the last one in particular) have 'smoothed' shifts by increasing clutch slippage. I for one, do not want the latest update.

91469972 04-18-2016 11:01 PM

I complained a few times about slippage to the dealer and then it started slipping when taking off from a dead start forward. Took to the dealer and they replaced it with my Fidelity extended warranty.

golfnutintib 04-18-2016 11:07 PM

mine is an 09 with pdk (photo at left)

definitely not torque-converter smooth at initial engagement from a standstill, be it backing up or going forward

there are mechanical clutches in there and they need to grab somehow... i have learned that being positive with the gas pedal helps,,,these trannies are worst when trying to 'guess' your intent and are confused/surprised

not saying floor it or be harsh, but using the gas pedal decisively helps when moving off from a standstill

ADias 04-18-2016 11:31 PM


Originally Posted by golfnutintib (Post 13211032)
mine is an 09 with pdk (photo at left)

definitely not torque-converter smooth at initial engagement from a standstill, be it backing up or going forward

there are mechanical clutches in there and they need to grab somehow... i have learned that being positive with the gas pedal helps,,,these trannies are worst when trying to 'guess' your intent and are confused/surprised

not saying floor it or be harsh, but using the gas pedal decisively helps when moving off from a standstill

Someone who gets it. :)

der Geist 04-19-2016 07:50 PM

What a perfect description!


Originally Posted by vbb (Post 13209796)
From what I have gathered, this is just one of the characteristics of the 997.2 PDK transmission.

The horror stories of PDK failure and how they can't be repaired, only replaced, are definitely attention grabbers. Unfortunately I did not know this until AFTER I purchased my car, and no, I do not have it under warranty anymore, so again, this has made me hyper-sensitive to any perceived "issues" with my car.

I have found that while it certainly doesn't behave like a full on manual transmission, it also doesn't behave like any other auto transmission I've ever driven. I have not noticed the rolling back while on a hill thing that you've mentioned, but I have noticed that little bit of hesitation, or slipping, when taking off from 1st or reverse right after starting the car, almost as if I was a newbie driving a stick and not sure of where the engagement point of the clutch was. Almost like a bit of a rev and then the "ahh, there it is" sensation. The first time this happened it scared the crap out of me because I was sure it was some early sign of PDK failure... but I believe it is just sort of the way it operates at times. When I'm taking off in the morning or after the car has been parked for awhile, I put it in gear, lift my foot from the brake and let the car engage on its own before giving it gas. That keeps me from feeling the little bit of hesitation.

As I have an '09, I just had the recommended PDK service performed about 2 months ago. The service mechanic said the car was running beautifully, and yes, it still does the hesitation move sometimes right after I've started it and put it in to gear.


voiceprint1 04-26-2016 01:08 PM

I have noticed this lately, when cold or sitting a few days, if I just "go", without really warming up, it's odd it almost seems like the engine kinda cuts out when reversing and turning 3/4lock? and it's a weird feeling , then it's all good, next start not an issue?

tapcon 04-26-2019 09:42 PM


Originally Posted by golfnutintib (Post 13211032)
mine is an 09 with pdk (photo at left)

definitely not torque-converter smooth at initial engagement from a standstill, be it backing up or going forward

there are mechanical clutches in there and they need to grab somehow... i have learned that being positive with the gas pedal helps,,,these trannies are worst when trying to 'guess' your intent and are confused/surprised

not saying floor it or be harsh, but using the gas pedal decisively helps when moving off from a standstill


Realize this is an old thread. As a Porsche noobs everything is on a learning curve that can go from exhilarating to terrifying, sometimes all in the same drive. For the first month I chased this slip around to the point that I was starting to think the car I just bought had a bad tranny. Then found this thread and for the past few weeks have been able to get it under control to where it only happens when I get sloppy with the gas pedal. Always appreciate a post with a chance to learn from experience - TY!


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