BondJ

Owning an out-of-warranty Porsche is definitely becoming a lottery. The company make fabulously dynamic and exciting cars but load them with unreliable tech. This thread is a perfect example. If I’ve understood correctly, Olddragger’s gearbox issue is with the electronics within the unit rather than the ironmongery. What I find most shocking is that there is no factory support beyond throwing away the busted item and paying through the nose for a replacement. Seems the most reliable Porsche is the one with the least options.

Petza914

I totally agree with you. Porsche isn't the same company it used to be and just seems to get worse as time goes by. Comparing the materials and the way things go together and come apart between my 997s and Cayenne to my 928s, the changes over those decades is obvious. My BMW X5 was the exact same experience you described with your Cayenne, whereas my low mileage Cayenne (50k now) hasn't needed a thing except oil changes, even though it's 13 years old now. I've done all the fluids, I'll do plugs and coils and the PDCC reservoir soon.

I have no interest in owning a Porsche any newer than my 2009 Cayenne and would buy older if adding anymore, ike a 964 speedster or a 993. Our 997s have been super - even better than our Infiniti, but the fear of bore scoring is always hanging there to detract from the some of the enjoyment. I would never own a PDK equipped Porsche and when searching for the recently acquired Q5 for my daughter immediately eliminated any cars equipped with the 7-speed S-tronic version of the PDK from Audi and only looked at 6-speed and 8-speed Tiptronic equipped vehicles.

DIYDanCars

I bought my 7 year old Cayenne Turbo (at the time) with 40k miles on it from the same Porsche dealer that sold it new and I didn't start having major problems until around 55k-60k miles. Simply put, it would probably be easier for me to tell you what I didn't replace than tell you what I did replace, that's how terrible my ownership experience was. A good friend of mine is a Master Porsche Certified mechanic and he has even told me the quality/reliability of these cars is "pretty bad" (his words). I should have listened to him, but some people have to learn the hard way, including me!

I agree. All of my Porsches from the 80s have been just as reliable as my Lexus. However, back then Porsche was a very different company (just like you said) and the engineers decided what materials to use and not the accountants. Today Porsche is run by bean counters who sole purpose is to increase profits at the expense of quality and reliability. I can't blame them though, because this strategy is working well for Porsche (huge profits) and buyers don't seem to care about the terrible quality and reliability in their cars because most new Porsche buyers don't keep them long enough to notice these problems.

VAGfan

Olddragger: The pump sucks fluid from the pan, thru the internal filter, then the fluid flows thru the external filter, to the heat exchanger, then to the Valve Body, to supply the solenoid valves.
Did you carefully inspect each solenoid valve pintle and bushing? See the post 168 (above), and read thru the entire 2nd link ("Valve Body Repair...")

Also, inside the valve body, are there any small cylindrical filters? (Not the flat screen filters that are part of some of the solenoid/valve subassemblies.

Did you disassemble and clean the red circled valves below?

Olddragger

Thanks for reading this thread! It is a continuing journey. I do agree with what is being said, very little to no factory support in diy or indie repairing your porsche. Porsche stepped into a market that is not familiar too them with the Macan. They made a one to two yearold, low mileage Macan into an affordable performance suv for the masses. People who never thought they would be able to afford a Porsche, all of a sudden could. It is their best seller. Even though this transmission has been having issues for over a decade Porsche elected to use it even knowing their was a class action suit against Audi concerning it. This class action was settled earlier this year for models up until 2014. Audi agreed to damages and an longer warrenty. 2015 Macans had this exact transmission. The last I heard, due to the number of repairs that are being requested through the dealerships, Porsche is taking a look at the situation. But, with everything else that is occurring with Porsche I do wonder if anything will be done. Meanwhile just look at the number of transmission related incidents that are occurring. To repeat myself in an earlier post, two general managers of Porsche service departments have told me that they have more transmission problems( not transfer cases)for the Macan than any other model. Why is that a surprise? It is already known as a defected unit.
This transmission could be the downfall of the Macan and that is a dang shame. The Macan is a good model design that hits those that need room for 4, a little hauling/towing capacity, great cosmetic quality, and good to excellent handling/braking/steering/ driving position. It would be sad for this to happen.
I would love a Macan with the 8 speed trans, or a 6 speed manual. Woo hoo!
My car was a $ 100,000 build...still have window sticker, in 2015. The fact that it has to be repaired with junkyard parts is unfathomable. I have never had to face such an issue with any of my previous 40 different cars I have owned.
It would be simple for Porsche to fix this. Just warrenty the trans like they did for the transfer case and make repair parts such as the mechatronic unit/ components and the clutch available to anyone at a fair price. That is all it would take.
I have never owned a vehicle that the manufactor treats its customers this way. I ran a heavily modified RX8 for years...and the side port rotary engine became a real problem for Mazda. Mazda stepped up and put a 100K mile warranty on it. The aftermarket figured out what was wrong with this engine and did substantially increase it's dependability. They had factory backing with parts and the tech was shared.
I ran a c6 ZO6 for some years and the LS7 engine had a weakness of dropping valves. Chevy stepped up somewhat and because of the aftermarket this problem was fixed. Parts and technology were available from Chevy.
Porsche needs to back their product in such a manner. They knew this transmission had a class action against it when they went into production of the Macan. They didn't make any improvements that can be seen and they placed an engine in front of it that was developing very close to the maximum amount of torque it could withstand. It was doomed from the start. There will be more and more transmission issues seen, mark my words. Meanwhile all we can do is wait.


Ok enough moaning and groaning lol... my reality is a bunch of parts on my workbench right now. Today I will ohm test all the solenoids, jerry rig a way to flush the coolant lines, reassemble the mech unit after ohm testing and then organize everything for reinstillation. Using valvoline dct fluid...,mets specs and is only $12 a liter! I have 8 liters on hand.
I will do the 3 minute reset thingy once filled...really don't know if this does anything, but it only takes 3 mins! I have the tires off, so I will test drive it gently on the stands. If all good, get it off and go for a drive. Then if all good I will do a 1 minute long happy dance! Then take it back to my indie for proper calibration with PIWIS. After that, it is straight to car max or caravana to sell! I will actually be sad because I really like the car. Once that is done at some point I will be looking for a 1955 chevy tastefully done for performance and daily driving ....yes with a/c, seat belts, disc brakes, auto transmission, power steering, reworked chassis and suspension. Gasp! It may even have a carburetor! Oh the thought!
But for now, on with the journey.
I should be done by this weekend...also have other work to do...who doesn't right?

Olddragger

Hey Vag! Yes there are approx 4 different micro fillers within the valve body itself. I would have to split the valve body itself in order to get to them. I am a little cautious in doing that...I don't know if the gasket between the two parts is reusable or not? It appears that the small filters have the same filtering ability of the the ones behind all the solenoids.
The mesh appears to be the same size. My old mech unit was split and the micro filters were super clean....go figure?
That is good info concerning the flow of the transmission fluid. I should have realized that as it does have a bypass valve in the unit....slap self in head! With this in mind, there is probably less chance this stuff madeit to the cooler itself. Still have to check.
I did remove all the solenoids, except for the ones on the tower, broke each one down as best you can and I inspected each of the brass looking cylinders within the solenoids with a magnifying glass and did not see any out of round wear.
It was strange the clutch #2 solenoid had a white cap and could be broken down all the way, but clutch number #1 had a black cap and could not. The pin at the end of it was completly free and moved easily. The little washer and ball was removed and there was a very small amount of the "slime" present. I find it interesting that there was more of this slime around these 2 solenoids than any others.
I washed the channels out under the solenoids with electronic cleaner and small engine brushes. There was not much. The valves that you have circled I did not take out. I don't think they are really affected. They are strictly mechanical and with just the small amount of this slime present within the valve body...elected not to go there. I did pay attention to the two pressure sensors on the tcu and it's mounting point on the valve body. There was a little bit of the slime present there.
I am finding so far enough to be a little hopeful, but have not had a eureka moment.
I don't understand why people have the idea that this transmission is hard to work on? It's really isn't.
As always appreciate all your help!

Olddragger

May have found my problem. The K2 N439 ohm reading was 16.6 tripled checked . K1 was 14.1 which is speck. This solenoid is also a little different...actually has a marking on it.
pic...


The one beside it is from my old mech unit and it specs out at 14.1. Why is this one different and why the etched marking? Hmmmmm?

mikebrinda

If a solenoid(s) has an open whenever it gets hot, whatever it controls is going to fail, and keep failing, until that solenoid is replaced. If something works as it should until hot, then consistently fails after it becomes heated, that's a sign of a solenoid with an open, especially if after the solenoid cools the device works properly again until hot and the works-fails-works-fails cycle repeats itself. If there is one solenoid that controls one specific thing, that is easy to troubleshoot because that solenoid itself and the single thing it controls fails in an obvious, and often visible manner. But when you have a single <insert whatever device here> that only works properly off of multiple solenoids operating with synchronized precision, then you add in extremely difficult solenoid access and zero real-time operational visibility of the solenoid(s), the only option is to replace all the solenoids because given these circumstances it is not practical to replace them one at a time. But when looking at replacing all the solenoids, parts and labor replacement cost enters the picture, especially when considering, for example, some other part that was not machined to spec and should have been discarded was for whatever reason used at the factory in the device and this part is the real problem.

Petza914

The orifice looks to be a different size as well, if that's what that is.

VAGfan

I don't think that minor discrepancy of the resistance measurement is your problem. If the windings open (the most common failure mode of a solenoid coil), the resistance would be infinite...not off by an Ohm or two. Also, a DMM ohmmeter is not that accurate for low resistances (say less than 50 Ohms), as the test leads themselves will contribute an Ohm or 2 to the displayed measurement. What does your meter display if you connect the two test leads together? That value must be subtracted from your measurement of the solenoids to compare with the 15 Ohm spec.
If any of these solenoid windings do open when hot, that would trigger a unique DTC trouble code itself, which you haven't gotten.

You could also take that K2 N439 solenoid, connect it to your ohmmeter, and put the solenoid in a toaster oven set to 200F, and monitor the DMM to see if the solenoid resistance suddenly jumps up to a much higher value as it warms up.

The change to the K2 N439 solenoid must have been some production change between your older 2015 Mechatronics and the 2017 replacement Mechatronics. I would put the white plastic one back into your 2017 unit. That white plastic portion is just the molded coil former, probably makes no difference.

The critical solenoids for fine control of the clutch engagement are the N440 (K2) and N436 (K1) clutch pressure regulator solenoids, I would examine them very carefully. That's where pintle and bushing wear is critical.
The N435 (K1) and N439 (K2) solenoid valves are just the ON/OFF control of the clutch fluid pressure coming from the clutch pressure regulator solenoids.

I would encourage you to pull out those U clips to disassemble those spring loaded mechanical plunger valves circled in red. They also seem to be a common failure area. One of these controls fluid cooling, which may be suspect, as your problems occur when your fluid gets up to normal operating temperatures.

I would guess that the valve body gasket would be reusable if you split the valve body, as long as the gasket comes off "clean", without any sealing surface damage.

I hope you don't mind me "pushing" you, but the root of the problem is not "magic", and it would be a shame to dump the car.

Olddragger

As always good feedback from everyone. It is very appreciated! Petra the actual little hole is the same size but the little depression before the oriface does show up better on the white one. Great eye!
Vag if the white "cap" was the only thing that was differant then I totally agree, but what about that etching? Where did that come from? I bet that is not factory. Possible repair job that is unknown? I don't know...just never seen that before.
Agreed on the main pressure solenoid and I did do a particularly good cleansing and eval on that one...actually both of that type. Those have channels that can be reached and flushed. There wasn't much there but I got what I could. The solenoid itself I cannot take apart. Those solenoids ...the main pressure ones have a little ball/plunger in one part and a spring plunger setup in another part. The spring plunger part can be removed by taking the little c clip out. If you shake the valve and can hear the little ball clicking then it is safe to assume it is clear. If it is not rattling then something is wrong. One cannot get tot the little ball part or visualize the brass ends of those solenoids without major disassembly.
I checked my ohm meter at its lowest setting and got 0.1. The solenoid measures sometimes at 16.9. Good idea about the oven! I will try that once the wife leaves for errands lol.
Dont worry about pushing me, I enjoy and appreciate guidance, especially when it makes common sense.
Since this is my last chance...what you say about checking those valves makes sense. I will add that to the check off list. Perhaps I can find a way to check them without spitting the valve body.

Olddragger

Mechatronic unit in. Adjusted pack to 32 Mandy the forks to neutral and it slide right in...lucky me! I did find a way to check those valves by manually just pushing on them, They actually feed from one of the rear oil tubes. You can hear the sound of there movement from there.
For some reason I don't have a good feeling that my efforts will result in a fix. Reason being I was getting the same code P17D6 pressure to high from the first mechatronic pack and from the second mechatronic pack. One never knows ..........
Will finish buttoning it up tomorrow. I am a little short on fluid and the other will not be here until Sunday. Will not forget to do the torque adaptation process.
Sigh.

VAGfan

DSG Throwing Code 8955 P17D4 - Valve 3 in Transmission Part 1 (audizine.com)

Some more reading....related to P17D400 DTC codes.

Olddragger

The more reading I do the more I realize a lot of the times it is a guessing game. Just for the sake of conversation, my transmission initial problem was the disintegration of a circuit board piece that "gummed" everything up and ended up causing a high pressure fault. That is logical and understandable......even though no one can tell me how the heck that happened? Ok, after experiencing huge and long learning curve, using a shotgun repair approach, I replaced the entire mechatronic unit sans the tcu. I kept the oridginal tcu.
Cleaned it out etc etc and now after it warms up I get the same fault and if I continue to drive it will go into limp mode. Ok I break it down again, find more dirty fluid and a moderate amount of black slime throughout. This slime does settle out some so perhaps what is happening is that it takes a little heat and agitation to get that slime into all the fluid and cause problems?
When I did the second tear down I found:
The outside filter was almost if not occluded from all this black stuff.
The internal filter did show signs of filtering more of this stuff out.
There we're small amounts of slime on K1, K2 solenoids but not in the ball/pinion area
there was a small amount of slime on the pressure and cooling solenoids but minimal in the channels of the valve body. The solenoid valves appeared to be working correctly
The K2 solenoid was taking 16.9 ohms which is high.
The was a large amount of this slime present on the bottom of the transmission pan that I had to scrub with a towel to remove......hmmmm.

Ok what I have done so far:
scrubbed everything down on the mechatronic pack.....there was none inside the trans...go figure.
removed every solenoid on the unit along with the tcu and checked/cleaned them all...best I could.
checked clutch....seemed ok...no slime in it that could be washed out.
No slime in the plump
swapped hydraulic pressure solenoids and check ohms under heat. ..they did ok remained under 5 at 160f.thanks vag for that suggestion.
put specked K 2 solenoid in
checked all the valves and regulators within the valve body itself...all clean and working
reinstalled making sure shift solenoids are set at 32 mm and forks are in the neutral position. It actually slipped in great!
made sure all connections are good and solid.

Now I guess we will see what will happen.
The rest of my fluid will get here tomorrow, I will fill according to procedure. First fill it until it runs out, crank it and go through the gears, then continue filling as engine is running, all the while watching temps. After that do the torque adaptation procedure, then take it for a drive. X fingers, need all the luck I can get.

Olddragger

Had to take a day off...got a little virus...not COVID!
Finished up today. Recharged my battery a little...it has been setting for a little, checked if there were any codes present( I only have a code reader). No codes present. I then did the trans reset procedure ( no load idle 3 mins blah blah). After that I took it for a drive for the longest I have driven it since it broke. Oil temp got over 200F and laser gun temp of the outside trans filter 168F.
It shifted great. No bumps, jerks or snorts! Very smooth and no clutch slippage. Downshift from 2nd to 1st was smooth. Take offs from stationary was smooth. No warnings in display, no codes. I only drove it for about 10 miles. Still don't trust it yet.
But I am cautiously optimistic!