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When I did the clutch pack disassembly video, even though I didn't name the brand, it was the raybestos products that I had looked at. If I needed to replace the clutch disks this is where I'd turn.
After looking closely at the disk dimensions it seems that the friction disks are identical between the two different transmissions (7DT45 v's 7DT70), and it's the steel disks that are different. The steels are thinner in the 7DT70 so they can install 6 pairs of disks rather than the 5 in the 7DT45. From my experience the steels rarely wear, and it's the friction disks that need replacing in automatic clutch packs (exactly the same type of clutch). So to replace the 7DT45 clutch friction disks would simply require the raybestos friction disks, and just use 5 of them instead of the 6 provided. From what I could see I speculate it would be easy to turn the 7DT45 clutch pack into a 7DT70 by purchasing the thinner steels from Raybestos and replacing.
Video below shows the disassembly and is cued to the correct position where I discuss the disks.
But my concern is:
1. What is the failure rate after a repair? Anyone who had done this, your input is very much appreciated.
2. Is there a way to prevent it from failing again? Driving style? Maintenance? Fluid change cycle? Temperature?
3. Is it necessary to also replace the speed sensor as well just to prevent a possible fail point in the future?
Not sure I saw a consolidated response, but for you and others:
1. My T-Design DS has been splashing about in fluid and measuring shift rod positions for two years and nearly 15,000 km, and functioning perfectly.
2. Not as I understand it, as the failure point is the construction of the OEM device (see above for detailed comment on component fail diagnostics). The newer ones use different components.
3. Some do, some do not. Depends on your appetite for cost vs. risk.
When I did the clutch pack disassembly video, even though I didn't name the brand, it was the raybestos products that I had looked at. If I needed to replace the clutch disks this is where I'd turn.
After looking closely at the disk dimensions it seems that the friction disks are identical between the two different transmissions (7DT45 v's 7DT70), and it's the steel disks that are different. The steels are thinner in the 7DT70 so they can install 6 pairs of disks rather than the 5 in the 7DT45. From my experience the steels rarely wear, and it's the friction disks that need replacing in automatic clutch packs (exactly the same type of clutch). So to replace the 7DT45 clutch friction disks would simply require the raybestos friction disks, and just use 5 of them instead of the 6 provided. From what I could see I speculate it would be easy to turn the 7DT45 clutch pack into a 7DT70 by purchasing the thinner steels from Raybestos and replacing.
Video below shows the disassembly and is cued to the correct position where I discuss the disks.
Great video, I somehow missed this one. You talked about cutting open the seam, how difficult was this and does it take machine tools? Or could it be done with something like a handheld cutting wheel?
Good info on the 7DT45 vs 7DT70, I didn't realize how similar the clutches are. The turbo PDK is rated at about 50% higher torque than the Carrera PDK, I find it hard to believe that extra clutch pad makes that big a difference. I know the turbo PDK has some forged internals in key places where in the NA PDK they are cast so perhaps that's the big difference.
I've got a turbo and have always been a little concerned I wouldn't be able to find a clutch if needed. Nice to know they can be rebuilt or even converted from a NA clutch if needed.
Great video, I somehow missed this one. You talked about cutting open the seam, how difficult was this and does it take machine tools? Or could it be done with something like a handheld cutting wheel?
Good info on the 7DT45 vs 7DT70, I didn't realize how similar the clutches are. The turbo PDK is rated at about 50% higher torque than the Carrera PDK, I find it hard to believe that extra clutch pad makes that big a difference. I know the turbo PDK has some forged internals in key places where in the NA PDK they are cast so perhaps that's the big difference.
I've got a turbo and have always been a little concerned I wouldn't be able to find a clutch if needed. Nice to know they can be rebuilt or even converted from a NA clutch if needed.
I had it cut open at a machine shop on a lathe. You would trash it otherwise I would think. This is the sort of thing a torque converter rebuild shop does all the time to rebuild a TC. They have specialty machines that cut it open and weld again once the internals are installed. I'd think it would be a pretty simple operation to have the disks in hand and take it to a TC rebuild shop and get them to do the work.
The critical part that I could see was to have it cut open exactly on the welded seam as I describe in the video so that the ledge below isn't damaged, which will set the height of the front plate correctly when being welded together.
From what I've seen on autos, changing the number of disks to alter the torque rating of the transmission is standard practice. It's just speculation on my part that this is the only change, as this is the only difference I've seen before between different versions of the same auto box . There might be some other components that have been strengthened in there as well, but without documentation that shows what's in there it would be very hard to know.
Another interesting PDK item on the market, URO offers an aluminum PDK pan with a replaceable filter for $230. Compare that to the plastic factory pan with a laughable MSRP of $490 and which must be tossed to replace the filter.
My concern with this is that we have no data that the new speed sensor is any more reliable than the old one. So you are replacing a known good part with one without a track record. If the speed sensor has failed then it makes perfect sense, a working (but yet unproven) sensor is better than a broken one. But replacing a part that hasn't failed?
We are working through some reliability issues on the Heathkit distance sensor project (not sure who coined that but I love the name) and learning an awful lot. This stuff can be tricky.
at the end of the day, the dealer didn't record my request of "replacing the speedsensor too".
So I am getting only the broken displacement sensor done.
But i get your point. Let's see how far the speed sensor will hold.
I am buying the T-Design sensor anyway later tho, just in case if it failed and I don't have to wait for the sensor again.
The car has been sleeping in the shop for a week now, it was a long holiday last week and my car chose a PERFECT time to broke down lol.
What a bad boy.
Since the car broke down and i had been doing a lot of research and the fact of "Porsche will replacing the whole unit ONLY" was pretty terrifying to me. Because the car is out of warranty.
But luckily the dealer said it is repairable, don't have to replace the whole thing. That was such a relief.
Plus I bought the car from a friend and he is willing to help the cost. It is the best it can be now.
Unfortunately, the dealer didn't get my additional request, so I guess I will be doing just the d-sensor.
Seems like I will have to test my luck with it now.
Given the build quality of the Porsche/ZF sensors vs. T-Design, I would HANDS DOWN go with a new speed sensor. Easy decision.
Fascinating to see a dealer in Bangkok be more creative than the U.S. dealers. Not surprising since U.S. dealers are parts replacers, generally speaking.
"14% side of things"... lol.
Since the car broke down and i had been doing a lot of research and the fact of "Porsche will replacing the whole unit ONLY" was pretty terrifying to me. Because the car is out of warranty. But luckily the dealer said it is repairable, don't have to replace the whole thing. That was such a relief. Plus I bought the car from a friend and he is willing to help the cost. It is the best it can be now.
Unfortunately, the dealer didn't get my additional request, so I guess I will be doing just the d-sensor. Seems like I will have to test my luck with it now.
I did consider this, however, I'm told that a billet version is better. Am told that if its not Billet, the material may have small air bubbles and may cause the pan to retain heat, in a hot climate country, this could spell disaster.
Not wanting to make a Chicken Little statements, I want to know how true is this?
I think it would save a lot of owners a lot of money, and help with heat dissipation as well.
Originally Posted by PV997
Another interesting PDK item on the market, URO offers an aluminum PDK pan with a replaceable filter for $230. Compare that to the plastic factory pan with a laughable MSRP of $490 and which must be tossed to replace the filter.
I did consider this, however, I'm told that a billet version is better. Am told that if its not Billet, the material may have small air bubbles and may cause the pan to retain heat, in a hot climate country, this could spell disaster.
Not wanting to make a Chicken Little statements, I want to know how true is this?
I think it would save a lot of owners a lot of money, and help with heat dissipation as well.
The billet pan also costs five times as much so yeah it should be a lot better, but five times? Come on. The billet pan has a higher capacity which could be helpful if you are a very serious tracker, so it's probably less likely to suck air under high g-forces. For 95+% of owners I'd say it's ridiculous overkill and a waste of money.
Having been around the Porsche brand for four decades now, it's pretty clear Porsche owners are an odd lot bordering on obsessive-compulsive (IMO). This makes them particularly susceptible to fear-mongering tactics, FUD marketing, and appeals to spend money for "peace of mind". Use common sense and push back against these absurd claims.
Edit: Adding to this that unlike the engine oil pump which is suspended from above, the PDK is designed to pull fluid through the bottom of the pan. And there are a couple of liters of fluid sitting in that pan. I've never heard of a PDK failure caused by sucking air. What we have seen is PDK temp faults during extreme tracking where the TCU shuts down the PDK until the fluid cools. If that's happened to you then the added capacity of a billet pan might make sense, as would a beefed up heat exchanger. For the overwhelming majority of owners this stuff is not needed.
But my concern is:
1. What is the failure rate after a repair? Anyone who had done this, your input is very much appreciated.
2. Is there a way to prevent it from failing again? Driving style? Maintenance? Fluid change cycle? Temperature?
3. Is it necessary to also replace the speed sensor as well just to prevent a possible fail point in the future?
Kris,
1. Our T-Design sensors failure rate so far is 0 if installed properly. We have two our biggest US installers here in this thread and 3 years history to attest to that.
And we constantly improve our designs based on our constant tests and research. We are on version 5 for distance sensors now.
2. We think temperature is somewhat loosely related to the original sensors fails. Our sensors don't care about anything P-cars can throw at it. We supply race teams too.
3. Our distance sensor has a 3 years perfect history so far. And a lifetime warranty on part itself.
As speed sensor is a newer part - it is a valid question - does it make sense to replace a working old part with a new, relatively unproven part. I can not answer that for you. But here's some points to consider:
- The components and (very important) technology we use in T-Design speed sensor - are based on what we learned from our extremely successful distance sensor.
- As a new part it went through long and vigorous tests in multiple cars. Including very hot climate tests. Similar to distance sensor - we learned A LOT from the tests and research. It was a long and sometimes frustrating process, many many versions, until we were able to build a part that works in the long run and that we are confident to offer.
- As we supply repair shops around the world and keep in touch with all our installers - we have a lot of data. And we do see cases where speed sensor fails 2-6 months after distance sensor replacement. Let me tell you - it's not fun for owners to go through the process again. We do not have any reversed cases so far
- We offer limited lifetime warranty on our speed sensor
- When you will see original part vs ours - you will wonder how that sorry looking plastic piece lasted that long
Also, usually we deliver in 3 to 5 days to any part of the world. So it's really not too late to order, if your shop doesn't have speed sensor in stock.
Need to tap into the hive mind again - 997.2 pdk started out with intermittent p1734 & p0700, couldn’t reverse when it happen, but would work fine after recalibrating with piwis. Thought distance sensor was on the verge of failing so I had a shop replacing it with t-design, worked fine for 200+ miles driving home but then got similar transmission emergency run and engine check light again, codes are now p1732 & p0700… this time it reverse fine so far but would stuck in a forward gear when errors pop. Restarting the car would get it to shift again but it errors again after a bit of driving. I have cleared the code for now but will try again in coming days to see if I can see a pattern, pretty sure it’s going to happen again.
Since it has a new distance sensor one would rule out sensor problem? What would be the next likely suspect? Distance sensor harness? TCU? TCU harness?
Last edited by byroncheung; 04-26-2023 at 09:34 PM.
I think the constant here is the P0700 DTC; believe that may point to the TCU. I did a very basic Google search, however and saw someone else with a similar issue on a 991.1, and the problem there ended up being bad wiring, so maybe double/triple check all the wires and connections as well?
I would check the pins at the TCU side connector. I've seen these wearing out to where they don't make good contact with the pins on the TCU. This would be more likely if you've had the connector on and off multiple times. Using a meter to probe can also cause this (don't ask me how I know). You can try to wiggle the wire bundle and or the connector while monitoring PIWIS for faults. This type of pin is easy to remove from the housing without a special tool (just need a small screwdriver). If you need to replace them you can get new ones here (this is the smaller size, the larger ones you can adjust the clamping pins with a small screwdriver if weak):
04-14-2023, 07:33 PM
