PDK Failure & Outcome Story
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McLaren997 (06-30-2022)
10-12-2018 | 08:10 PM
#141
Race Car
Joined: Mar 2013
Posts: 4,410
Likes: 714
From: Northern Virginia
Coasting and the auto start/stop function
Where the situation allows, the coasting function is possible. By opening the clutches, the engine is decoupled from the transmission to prevent deceleration caused by engine braking. In this way, optimum use is made of the vehicle’s momentum, allowing it to coast for longer distances. This translates into a significant fuel saving. The auto start/ stop function included as standard also reduces fuel consumption.From the imanual for the 991.2:
Driving in coasting mode
Coasting is driving with the engine disengaged at idle speed without the engine braking effect. The standard function is designed to increase efficiency and driving comfort, and is active by default. Coasting occurs after the accelerator pedal is fully released. When the accelerator pedal is pressed again the engine is quickly and easily engaged and coasting stops.
Prerequisites for automatic coasting mode
- Driving in selector lever position D.
- Cruise control function cannot be active.
- Engine, transmission and battery have reached operating temperature.
- No major inclines or slopes.
When adopting an anticipatory driving style, depending on the traffic, coasting can be initiated manually to increase efficiency. To do so use the gearshift paddle or the selector lever to manually shift up beyond the highest possible gear.
The same applies to the active use of the engine brake, for example driving up to a vehicle in front or a red light. More forceful braking or operating the gearshift paddle or selector lever can activate efficient engine overrun shut-off in these situations.
Personal note:
Although it says that it cannot be used with cruise control, I swear that when I use ACC (991.2), it will use the coasting function from time to time (going down hills) and kick it into neutral (~ 500-600 rpm). My previous 991.1 with ACC (and my previous 991.1 with cruise control only - I am on my third 991 lol) did not coast when the cruise control (or ACC) was on.
10-13-2018 | 10:19 AM
#144
Rennlist Member
Joined: Nov 2015
Posts: 1,141
Likes: 154
From: Northern VA and Central FL
For those thinking that a manual tranny would fix the problem.... it might... but just FYI the 991 manual tranny is actually a PDK tranny with a different clutch and an elaborate mechanism to map the gear shift inputs to the two-path (even/odd gears) shifting used by the PDK. If most of the PDK problems being reported happen to be in the clutch or auto-shifting mechanism then switching to a car with a manual tranny would help. Using a single transmission base for both allowed for a significant manufacturing cost savings of course..
My problem happened on the back straight at VIR while shifting from 3 to 4, there simply was no 4. We determined that it wasn’t cable linkage related so I left the event early and drove straight to the dealership. They spent about two hours inspecting everything to make sure I hadn’t applied any warranty violating modifications (this is another important point - be careful about mods while under warranty). Once they were convinced everything was properly Porsche they took my car for a new transmission. All in all it took about a week, I replaced the clutch while they were at it since they offered to do so at 1/2 hour of labor.
Needless to say my CPO has more than paid for itself
10-13-2018 | 10:44 AM
#145
Rennlist Member
Joined: Oct 2016
Posts: 633
Likes: 32
From: So Cali
in regards to Fidelity warranty, I have been reading the contract closely, I would say that PDK is FULLY covered under Gold plus (including the transmission cooler etc.) I dont see why it wouldn't be
the basic power train covers the transmission and all internally lubricated parts (which to my read is EVERYTHING of the transmission, gears, housing, plates torque converters, valves etc etc.)The Gold adds the trans oil pan, kick down link, and vacuum modulator and trans mounts. The Gold Plus adds trans cooler...which it seems like that's everything under "Transmission" . I will say that I will no go to Gold or Silver plan because there are some things that's not covered in those plans under the transmission section (as stated above)
I also ask my SA and he suggest going with Platinum (of course) but he said Gold plus will pretty much covers all the big ticket items (with a few exceptions of smaller, usually electrical things like hoses and switches etc. which will be a small cost )
I am still under CPO, but in a year or so I am going to go with a 6-7 years low miles Fidelity Gold Plus plan
the basic power train covers the transmission and all internally lubricated parts (which to my read is EVERYTHING of the transmission, gears, housing, plates torque converters, valves etc etc.)The Gold adds the trans oil pan, kick down link, and vacuum modulator and trans mounts. The Gold Plus adds trans cooler...which it seems like that's everything under "Transmission" . I will say that I will no go to Gold or Silver plan because there are some things that's not covered in those plans under the transmission section (as stated above)
I also ask my SA and he suggest going with Platinum (of course) but he said Gold plus will pretty much covers all the big ticket items (with a few exceptions of smaller, usually electrical things like hoses and switches etc. which will be a small cost )
I am still under CPO, but in a year or so I am going to go with a 6-7 years low miles Fidelity Gold Plus plan
10-13-2018 | 11:59 PM
#146
Rennlist Member
Joined: Oct 2018
Posts: 847
Likes: 260
in regards to Fidelity warranty, I have been reading the contract closely, I would say that PDK is FULLY covered under Gold plus (including the transmission cooler etc.) I dont see why it wouldn't be
the basic power train covers the transmission and all internally lubricated parts (which to my read is EVERYTHING of the transmission, gears, housing, plates torque converters, valves etc etc.)The Gold adds the trans oil pan, kick down link, and vacuum modulator and trans mounts. The Gold Plus adds trans cooler...which it seems like that's everything under "Transmission" . I will say that I will no go to Gold or Silver plan because there are some things that's not covered in those plans under the transmission section (as stated above)
I also ask my SA and he suggest going with Platinum (of course) but he said Gold plus will pretty much covers all the big ticket items (with a few exceptions of smaller, usually electrical things like hoses and switches etc. which will be a small cost )
I am still under CPO, but in a year or so I am going to go with a 6-7 years low miles Fidelity Gold Plus plan
the basic power train covers the transmission and all internally lubricated parts (which to my read is EVERYTHING of the transmission, gears, housing, plates torque converters, valves etc etc.)The Gold adds the trans oil pan, kick down link, and vacuum modulator and trans mounts. The Gold Plus adds trans cooler...which it seems like that's everything under "Transmission" . I will say that I will no go to Gold or Silver plan because there are some things that's not covered in those plans under the transmission section (as stated above)
I also ask my SA and he suggest going with Platinum (of course) but he said Gold plus will pretty much covers all the big ticket items (with a few exceptions of smaller, usually electrical things like hoses and switches etc. which will be a small cost )
I am still under CPO, but in a year or so I am going to go with a 6-7 years low miles Fidelity Gold Plus plan
10-24-2018 | 07:54 PM
#147
Burning Brakes
Joined: Aug 2016
Posts: 1,141
Likes: 55
I can vouch for this. I have a 2013 S with a 7MT that failed similar to what the OP describes - I lost reverse and all even gears. One savings grace of the MT was that I was able hobble home using the odd numbered gears. BTW, you don’t realize how tall 2nd gear is until you skip past it, you have to run 1st pretty much to the top to get enough speed to go to 3rd.
My problem happened on the back straight at VIR while shifting from 3 to 4, there simply was no 4. We determined that it wasn’t cable linkage related so I left the event early and drove straight to the dealership. They spent about two hours inspecting everything to make sure I hadn’t applied any warranty violating modifications (this is another important point - be careful about mods while under warranty). Once they were convinced everything was properly Porsche they took my car for a new transmission. All in all it took about a week, I replaced the clutch while they were at it since they offered to do so at 1/2 hour of labor.
Needless to say my CPO has more than paid for itself
12-25-2018 | 11:04 PM
#148
Racer
Joined: Mar 2016
Posts: 281
Likes: 73
Does this issue also effect Porsche in model years years (say 2002 to 2009)? Or is it only for fairly newer Porsches? I only ask because I am fairly new to Porsche and am looking/hoping to get a late 996 or an early 997 trip transmission, thanks in advance.
12-26-2018 | 12:38 AM
#149
Rennlist Member
Joined: Aug 2012
Posts: 6,243
Likes: 1,305
From: Pac NW
Both our 991s are 7 speed and I noticed something interesting today - I have the window sticker for both and I noticed that the 2015 (base) lists the country of origin for the transmission as Japan, while the 2013 (S) lists the country of origin for the transmission as Germany. Not sure if this is a “base vs S” thing (doubtful - aren’t the transmissions the same between them?), “2013 vs. 2015” thing (that they were manufactured at one location to start, but were ultimately moved over to another facility), or what...I will say the 2015 transmission “feels” different in clutch engagement. Am I saying this is the source of failures? Absolutely NOT - just looking to see if there is a pattern or a higher likelihood in one scenario vs another. Curious as to what others think. -Dom
12-26-2018 | 08:13 AM
#150
Rennlist Member
Joined: Jun 2013
Posts: 1,757
Likes: 144
From: San Francisco Bay Area
Originally Posted by pkalhan
Does this issue also effect Porsche in model years years (say 2002 to 2009)? Or is it only for fairly newer Porsches? I only ask because I am fairly new to Porsche and am looking/hoping to get a late 996 or an early 997 trip transmission, thanks in advance.