Transmission problems...beware
09-02-2023, 12:39 AM
#317
Rennlist Member
Right. There was an assertion that sport mode produced less heat, but if slippage is the main heat generation mechanism and there is slippage in both normal and sport modes for drivability, then the assertion seems to be incorrect.
Just trying to determine if I should be driving continuously in sport mode or not. If the shift frequency is not a major factor, only time at idle, then it should not matter and either mode produces the same amount of heat.
Just trying to determine if I should be driving continuously in sport mode or not. If the shift frequency is not a major factor, only time at idle, then it should not matter and either mode produces the same amount of heat.
Sport mode has less total accumulated wear, all else being equal, because of less clutch slip during gear changes, while clutch slip at idle is the same as in normal or comfort mode.
Theoretically, useful life could be extended by driving in sport mode 100% of the time. But there are certainly more variables in play that could reduce or negate the sport mode advantage from less slip during gear changes.
In practical terms it's unknowable. There are no, and never will be, any controlled real-world comparisons of sport mode 100% of the time for xx years, vs normal/comfort mode for the same time period and the same use case (speed, load, etc.).
09-02-2023, 12:08 PM
#318
Advanced
There is heat, and then there is total accumulated wear. Slip = heat = wear.
Sport mode has less total accumulated wear, all else being equal, because of less clutch slip during gear changes, while clutch slip at idle is the same as in normal or comfort mode.
Theoretically, useful life could be extended by driving in sport mode 100% of the time. But there are certainly more variables in play that could reduce or negate the sport mode advantage from less slip during gear changes.
In practical terms it's unknowable. There are no, and never will be, any controlled real-world comparisons of sport mode 100% of the time for xx years, vs normal/comfort mode for the same time period and the same use case (speed, load, etc.).
Sport mode has less total accumulated wear, all else being equal, because of less clutch slip during gear changes, while clutch slip at idle is the same as in normal or comfort mode.
Theoretically, useful life could be extended by driving in sport mode 100% of the time. But there are certainly more variables in play that could reduce or negate the sport mode advantage from less slip during gear changes.
In practical terms it's unknowable. There are no, and never will be, any controlled real-world comparisons of sport mode 100% of the time for xx years, vs normal/comfort mode for the same time period and the same use case (speed, load, etc.).
09-02-2023, 07:39 PM
#319
There is heat, and then there is total accumulated wear. Slip = heat = wear.
Sport mode has less total accumulated wear, all else being equal, because of less clutch slip during gear changes, while clutch slip at idle is the same as in normal or comfort mode.
Theoretically, useful life could be extended by driving in sport mode 100% of the time. But there are certainly more variables in play that could reduce or negate the sport mode advantage from less slip during gear changes.
In practical terms it's unknowable. There are no, and never will be, any controlled real-world comparisons of sport mode 100% of the time for xx years, vs normal/comfort mode for the same time period and the same use case (speed, load, etc.).
Sport mode has less total accumulated wear, all else being equal, because of less clutch slip during gear changes, while clutch slip at idle is the same as in normal or comfort mode.
Theoretically, useful life could be extended by driving in sport mode 100% of the time. But there are certainly more variables in play that could reduce or negate the sport mode advantage from less slip during gear changes.
In practical terms it's unknowable. There are no, and never will be, any controlled real-world comparisons of sport mode 100% of the time for xx years, vs normal/comfort mode for the same time period and the same use case (speed, load, etc.).
Last edited by DHL; 09-02-2023 at 07:45 PM.
09-02-2023, 07:41 PM
#320
09-02-2023, 10:31 PM
#321
Rennlist Member
Agree for the most part, but the issue at hand is heat, not wear, since the obvious failure mode in the OP trans is heat. It has also be speculated that sport mode produces less heat due to less frequent shifts. Shifting in and of itself does not produce the majority of heating, its slippage during idle at rest. This slippage is no different between the modes so I fail to see how using sport mode would make any difference at all. And I fully agree that there has been little to no documention for either case, so we probably will not know for certain. As a previous poster has suggested, shifting into neutral would prevent the slippage as would re-enabling start stop. However neither of these options is really attractive to most drivers.
Friction plates have a finite life, measured in Watt-hours. Each increment of slip is an increment of power (Watts, or torque x angular velocity) over time (seconds) absorbed by the clutch plates which is converted into wear + heat.
Identical principle of operation as the brake pads and rotor, where heat is generated, and pad+rotor material separates over time. Brakes are obviously a dry clutch example, vs the PDK wet clutch.
Last edited by chassis; 09-04-2023 at 10:45 AM.
11-21-2023, 05:19 AM
#322
@VAGfan Read this entire thread from start to finish and your expertise is hugely appreciated. I have a customer car (2016 Macan S) that arrived in Limp Mode with the following codes:
P17D400- CLUTCH VALVE IN GEAR TRAIN HALF 1 (MECHANICAL FAULT)
P17D500- CLUTCH VALVE IN GEAR TRAIN HALF 2 (MECHANICAL FAULT)
P17D800- TORQUE LIMITATION DUE TO CLUTCH TEMPERATURE
Did a full fluid and filter flush (light metallic silt in the fluid) and drove the car. Car drove perfect, no issues at all, but after about 30 minutes, we stopped the car and let it idle for another 30 minutes to build some more heat and when we tried to drive it again, the vehicle immediately went into limp mode again.
Next day drove for an hour, no issues at all.
Next day, left vehicle to idle long term, fluid got to 219 degree's farenheit and immediately when putting it into Reverse, we got the no R possible and engine light codes.
Scanned and only had:
P17D400- CLUTCH VALVE IN GEAR TRAIN HALF 1 (MECHANICAL FAULT)
P17D500- CLUTCH VALVE IN GEAR TRAIN HALF 2 (MECHANICAL FAULT)
Not exactly the errors that original posted had, but similar behavior in that it drives great, but then misbehaves when it gets some heat in it.
My understanding is that if I can get an entire mechatronic unit from Porsche, that should solve the issues most have run into, correct?
We have a cloned PIWIS (I believe PIWIS 2). Would that be able to do the entire programming process for the vehicle?
Looking forward to your insight.
Thanks a ton.
P17D400- CLUTCH VALVE IN GEAR TRAIN HALF 1 (MECHANICAL FAULT)
P17D500- CLUTCH VALVE IN GEAR TRAIN HALF 2 (MECHANICAL FAULT)
P17D800- TORQUE LIMITATION DUE TO CLUTCH TEMPERATURE
Did a full fluid and filter flush (light metallic silt in the fluid) and drove the car. Car drove perfect, no issues at all, but after about 30 minutes, we stopped the car and let it idle for another 30 minutes to build some more heat and when we tried to drive it again, the vehicle immediately went into limp mode again.
Next day drove for an hour, no issues at all.
Next day, left vehicle to idle long term, fluid got to 219 degree's farenheit and immediately when putting it into Reverse, we got the no R possible and engine light codes.
Scanned and only had:
P17D400- CLUTCH VALVE IN GEAR TRAIN HALF 1 (MECHANICAL FAULT)
P17D500- CLUTCH VALVE IN GEAR TRAIN HALF 2 (MECHANICAL FAULT)
Not exactly the errors that original posted had, but similar behavior in that it drives great, but then misbehaves when it gets some heat in it.
My understanding is that if I can get an entire mechatronic unit from Porsche, that should solve the issues most have run into, correct?
We have a cloned PIWIS (I believe PIWIS 2). Would that be able to do the entire programming process for the vehicle?
Looking forward to your insight.
Thanks a ton.
11-21-2023, 05:22 AM
#323
Also, I found this TSB (file:///Users/grantliban/Downloads/MC-10207223-0001.pdf). Is there any concern or reason to send the radiator/trans cooler combo out to get flushed and cleaned or is that unnecessary at this point? I also saw the filter you posted (https://maktrans.net/FK-0B5-Q5) which seemed interesting. Would that be a worth while addition in these cases as well (mechatronic replacement) or not?
Thanks again,
Grant
Thanks again,
Grant
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chassis (11-21-2023)
11-21-2023, 11:06 AM
#324
You could try pulling the Mechatronics out and just replacing the two "Circuit Boards", cheapest thing to try, but I think that probably will not solve your issue. (Your DTC codes are not "Electrical Malfunction" codes).
Audi B8/B8.5 S4 Quattro 3.0T Drivetrain DSG Transmission - 0B5398009F - Mechatronics Repair Kit 0B5398009F (0B5 398 009 F) (ecstuning.com)
The most likely fix (but more $$) is to get a new or rebuilt Mechatronics unit (just the valve body part, not with a new TCU), and install the original TCU onto the new valve body. Then, no TCU programming is needed (to write the VIN into it (needed for the immobilizer).
But, you will need to run the full Mechatronics adaptations/calibration with your PIWIS.
Porsche sells the Mechatronics unit (9A7-325-025-01), as a replacement part. And it includes a new TCU, which you probably don't need. Sunset Porsche has it currently on-sale for $3404.
2019-2021 Porsche Macan Valve Body 9A7-325-025-01 | Sunset Porsche Parts
Valve body (mechatronics) without electronic control unit, automatic transmission 0B5 (DL501) 0B5325025T 0B5325031N regenerated (maktrans.net)
Concerning the TSB, if you have evidence of engine coolant mixing with the DSG fluid, then that is a major problem for the DSG internals. There is a test kit available to see if the drained DSG fluid has any contamination from coolant. As a precaution, you could just use a fluid pump and fresh fluid and flush out the PDK fluid cooler and line, no need to send that "out" for that.
Overall, the cheapest way (but most time consuming) fix is to take the original valve body completely apart, clean out all the passages, replace all the gaskets, replace all the solenoids, and re-assemble with the original TCU, and use new circuit boards. There are instances where the root-cause of hot-only PDK issues is the gasket between the two halves of the lower valve-body section, which only seems to leak with hot fluid.
Valve body plate gasket kit DL501 0B5 | 08-up (maktrans.net)
Lots of these parts can be found on Amazon at Ebay, but maybe of questionable quality?? Depends how much you want to gamble versus the higher priced sources like ECS Tuning, Porsche, and Maktrans.
Good luck !!
Audi B8/B8.5 S4 Quattro 3.0T Drivetrain DSG Transmission - 0B5398009F - Mechatronics Repair Kit 0B5398009F (0B5 398 009 F) (ecstuning.com)
The most likely fix (but more $$) is to get a new or rebuilt Mechatronics unit (just the valve body part, not with a new TCU), and install the original TCU onto the new valve body. Then, no TCU programming is needed (to write the VIN into it (needed for the immobilizer).
But, you will need to run the full Mechatronics adaptations/calibration with your PIWIS.
Porsche sells the Mechatronics unit (9A7-325-025-01), as a replacement part. And it includes a new TCU, which you probably don't need. Sunset Porsche has it currently on-sale for $3404.
2019-2021 Porsche Macan Valve Body 9A7-325-025-01 | Sunset Porsche Parts
Valve body (mechatronics) without electronic control unit, automatic transmission 0B5 (DL501) 0B5325025T 0B5325031N regenerated (maktrans.net)
Concerning the TSB, if you have evidence of engine coolant mixing with the DSG fluid, then that is a major problem for the DSG internals. There is a test kit available to see if the drained DSG fluid has any contamination from coolant. As a precaution, you could just use a fluid pump and fresh fluid and flush out the PDK fluid cooler and line, no need to send that "out" for that.
Overall, the cheapest way (but most time consuming) fix is to take the original valve body completely apart, clean out all the passages, replace all the gaskets, replace all the solenoids, and re-assemble with the original TCU, and use new circuit boards. There are instances where the root-cause of hot-only PDK issues is the gasket between the two halves of the lower valve-body section, which only seems to leak with hot fluid.
Valve body plate gasket kit DL501 0B5 | 08-up (maktrans.net)
Lots of these parts can be found on Amazon at Ebay, but maybe of questionable quality?? Depends how much you want to gamble versus the higher priced sources like ECS Tuning, Porsche, and Maktrans.
Good luck !!
Last edited by VAGfan; 11-21-2023 at 02:51 PM.
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11-21-2023, 02:24 PM
#325
Immensely appreciate the insight!
So if I understand correctly, Buy this unit (https://maktrans.net/Gidroblok-uprav...0B5325031N-B-U) transfer the old TCU over to this one, install and do a PDK calibration on PIWIS and we've got all of our bases covered for a successful repair? Obviously new fluid/filter/ect.
Or buy a full unit from Porsche Suncoast and transfer the TCU as well, more money, but new and "Porsche" vs. rebuilt, correct?
So if I understand correctly, Buy this unit (https://maktrans.net/Gidroblok-uprav...0B5325031N-B-U) transfer the old TCU over to this one, install and do a PDK calibration on PIWIS and we've got all of our bases covered for a successful repair? Obviously new fluid/filter/ect.
Or buy a full unit from Porsche Suncoast and transfer the TCU as well, more money, but new and "Porsche" vs. rebuilt, correct?
The following users liked this post:
grantrr (11-21-2023)
The following users liked this post:
grantrr (11-21-2023)
