Transmission Conundrum fo 2004 CS

[stutzchris]

Good Morning Folks.  I need some advice on MY2004 CS two years and 45,000 km ago.  Since I purchased the vehicle the transmission shifting has been a bit off.  I liken it to the shifting on my Durango I traded in on the Cayenne, not that smooth but adequate which surprised me that the CS was not better.  I had what I would say, less than smooth shift between 2-3 and 4-5.  They were not horrible and I accepted that was the way it was.  It was not until we purchase a 2006 CS that I learned the shifting should be smooth and seamless. 

 

Recently, the past 4 months the transmission in MY2004 has been very interesting.  At times the shifting is smooth, other times there are the issues I described above, other times there are slips where the 2-3 & 4-5 revs plus 800 RPMs before it shifts and these are all while driving sensibly in the city or on the highway without being aggressive shifting at 3000-3500 RPM.  When being aggressive with the throttle, which I try not to do now, There is a massive clunk when down shifting and or up shifting with the shift points around 5000 RPM. The clunk is so massive that it feels like the transmission has been knocked out of the bottom.  There is no consistency to the issues.  The described can all happen on the same drive or none at all or alternate or repeat. 

 

I have spent hours researching the many post on these issues and tried to decipher the what seems to be thousands forum mechanics opinions on the issues causes. (ie: Fluid Issues, TCU/TCM, Valve Body, Stepper Motor, Tranny Mounts and the list goes on)  That said, I called the local dealership to book and appointment to have the Fluid changes since I am unsure if it has ever been done.  MY2004 has 175,000ish kms on it I thought it might be  place to start.  I do most of most of the maintenance, crawling under and doing an oil change is one thing, but the messiness of this one has me a,little less than enthused to do. 

 

I called the Calgary Porsche Dealership and explained I wished to have the transmission fluids and filter changed. The service manager was shocked I wanted a transmission flush and filter change.  He said that he doesn't recommend it since that the fluids should last 16 years.  The price was around $1000, 600 for parts and fluids and rest in shop time. I was a little surprised at the fee, but this is Calgary and no auto repair is cheap here and I just want it done right.  Is this good advice with that interval?  Independent shops are an option, but take weeks to get booked in and they are "ce la vie" if you need it quick  The dealership has been good to me with issues and service and booking.

 

The service manager has recommended I bring it in and they do a diagnosis and update the TCU/TCM.  I then drive it for a while and see if it is resolved. He explained that hes doesn't want me to spend money unnecessary fixes.  I realize that is the valve body is going to be replaced that the flush and fluids will be incorporated into the repair.  He quoted around $2500 for the Valve body replacement cost.  The Cayenne is paid for so This type of repair cost is warranted since I only have normal vehicle running cost on it. 

 

I guess I am asking if this seems to be a reasonable plan of action? 

 

Thanks in advance!

 

 

 

 

[JFP in PA]

Good Morning Folks.  I need some advice on MY2004 CS two years and 45,000 km ago.  Since I purchased the vehicle the transmission shifting has been a bit off.  I liken it to the shifting on my Durango I traded in on the Cayenne, not that smooth but adequate which surprised me that the CS was not better.  I had what I would say, less than smooth shift between 2-3 and 4-5.  They were not horrible and I accepted that was the way it was.  It was not until we purchase a 2006 CS that I learned the shifting should be smooth and seamless. 

 

Recently, the past 4 months the transmission in MY2004 has been very interesting.  At times the shifting is smooth, other times there are the issues I described above, other times there are slips where the 2-3 & 4-5 revs plus 800 RPMs before it shifts and these are all while driving sensibly in the city or on the highway without being aggressive shifting at 3000-3500 RPM.  When being aggressive with the throttle, which I try not to do now, There is a massive clunk when down shifting and or up shifting with the shift points around 5000 RPM. The clunk is so massive that it feels like the transmission has been knocked out of the bottom.  There is no consistency to the issues.  The described can all happen on the same drive or none at all or alternate or repeat. 

 

I have spent hours researching the many post on these issues and tried to decipher the what seems to be thousands forum mechanics opinions on the issues causes. (ie: Fluid Issues, TCU/TCM, Valve Body, Stepper Motor, Tranny Mounts and the list goes on)  That said, I called the local dealership to book and appointment to have the Fluid changes since I am unsure if it has ever been done.  MY2004 has 175,000ish kms on it I thought it might be  place to start.  I do most of most of the maintenance, crawling under and doing an oil change is one thing, but the messiness of this one has me a,little less than enthused to do. 

 

I called the Calgary Porsche Dealership and explained I wished to have the transmission fluids and filter changed. The service manager was shocked I wanted a transmission flush and filter change.  He said that he doesn't recommend it since that the fluids should last 16 years.  The price was around $1000, 600 for parts and fluids and rest in shop time. I was a little surprised at the fee, but this is Calgary and no auto repair is cheap here and I just want it done right.  Is this good advice with that interval?  Independent shops are an option, but take weeks to get booked in and they are "ce la vie" if you need it quick  The dealership has been good to me with issues and service and booking.

 

The service manager has recommended I bring it in and they do a diagnosis and update the TCU/TCM.  I then drive it for a while and see if it is resolved. He explained that hes doesn't want me to spend money unnecessary fixes.  I realize that is the valve body is going to be replaced that the flush and fluids will be incorporated into the repair.  He quoted around $2500 for the Valve body replacement cost.  The Cayenne is paid for so This type of repair cost is warranted since I only have normal vehicle running cost on it. 

 

I guess I am asking if this seems to be a reasonable plan of action? 

 

Thanks in advance!

 

If there is a single factor contributing to problems with the transmissions in these vehicles, it is the recommended service intervals.  I'm sorry, but there is no transmission fluid made that will withstand 16 years of daily use.  At one point, Porsche recommended 90K miles as the optimum interval; again way, way too long.

 

Like most modern electronically controlled automatic gearboxes, the trans in your car has multiple solenoid valves and controls circuits that have incredibly small passageways.  Over time, normal wear clutch dust, other debris, and even some varnish like materials will build up and clog these passageways, leading to everything from rough shifting to multiple fault codes, and eventually will cause the unit to drop into a kind of "limp mode".  At that point, you are in for some major $ expenditures as the unit will at a minimum need a full service and a replacement valve body, or even a complete trans replacement (dealers are getting about $10K for that). 

 

Now comes the kicker:  Normal servicing (a bit messy but doable DIY project) does not change all the fluid in the trans.  A drain, filter swap, and refill only gets less than half the old fluid out.  Because  of the way the trans is designed, a large portion of the fluid is in the torque converter and cooler which does not gravity drain during a service (again, because of the design, pressure flushing of the entire system is not an easy task on the Porsche Tiptronic).  So every time you service the unit, you are only replacing part of the fluid; and some very dirty old fluid remains and you are depending upon dilution with clean fresh fluid to help disperse any remaining crud, which is all the more reason to short the service intervals.

 

We normally shorten the service intervals on Tip vehicles to no more than 40K miles for normal use, sooner for ones that tow or see more heavy usage. When I tell customer that, I usually get raised eyebrows or comments about the factory or dealer recommendations; and my response is that fluid is cheap, replacement valve bodies (just scan through the Cayenne section on any Porsche forum to see how often that subject comes up), or replacement transmissions, even used ones, ain't by any means cheap.

 

If I were you, and as you have not mentioned any codes being thrown by the unit, I would ignore the dealer and get the trans at least serviced.  You just might be surprised how well it may respond to a simple oil change.

[stutzchris]

Thanks JFP ....

 

I am not getting any codes.  I have scanned with Durametric.  The service manager found that interesting.  So, if I read you right I should request a "complete fluid change? And ignore the "don't change the fluids." Would it be suggested to upgrade the TCU at that time as well? 

 

Thanks

[JFP in PA]

Thanks JFP ....

 

I am not getting any codes.  I have scanned with Durametric.  The service manager found that interesting.  So, if I read you right I should request a "complete fluid change? And ignore the "don't change the fluids." Would it be suggested to upgrade the TCU at that time as well? 

 

Thanks

 

Unless there is a TSB for the car recommending a TCU update, or the car was throwing codes, I would leave the TCU alone.  Changing the control unit when it is not needed is just an added $500+ expense for no apparent reason.  But get the fluid and filter changed ASAP.

[stutzchris]

Thank you for the advice.  I will do so ... It is booked for Thursday ...

[stutzchris]

I just spoke to the Service manager again.  I stated I just wanted to go ahead with the flush and fluid change.  He stated that his shop foreman does not recommend it that 9 times out of 10 it is a vale body issue even though it is not throwing codes.  They are going to do the diagnostic but feel it won't show anything since I am not getting codes and they will drive it to see what it is doing.  He stated that when they do the flush it can create more problems than before it is flushed. 

 

In theory I get what he is saying.  If we flush the service the transmission and it does not rectify the issue I just flushed that money down the drain, pun intended.  He also stated even though I do not show any leaks on the garage floor, there could be leaks migrating in other direction like the wiring harness.  I guess we will see ... I will lean toward heavily toward your advice JFP.  I have had transmissions serviced before an they always say the fluid change is a bad idea.  I don't get why.  He could not answer if there are any TSBs.

 

Thanks

Edited January 10, 2015 by stutzchris

[JFP in PA]

I just spoke to the Service manager again.  I stated I just wanted to go ahead with the flush and fluid change.  He stated that his shop foreman does not recommend it that 9 times out of 10 it is a vale body issue even though it is not throwing codes.  They are going to do the diagnostic but feel it won't show anything since I am not getting codes and they will drive it to see what it is doing.  He stated that when they do the flush it can create more problems than before it is flushed. 

 

In theory I get what he is saying.  If we flush the service the transmission and it does not rectify the issue I just flushed that money down the drain, pun intended.  He also stated even though I do not show any leaks on the garage floor, there could be leaks migrating in other direction like the wiring harness.  I guess we will see ... I will lean toward heavily toward your advice JFP.  I have had transmissions serviced before an they always say the fluid change is a bad idea.  I don't get why.  He could not answer if there are any TSBs.

 

Thanks

 

As I mentioned earlier, valve body issues are common on these vehicles, particularly those that follow the recommended service intervals.  Of all the things in that transmission, the oil is by far the cheapest, as well as one of the most important.

 

We have has more than one car in the shop that showed drivability issues (weird or inconsistent shifting, particularly in the cold) that went away with a simple oil and filter change.

 

The shop manger has a point, oil or water leakage into the connectors on the transmission communications cables are a real problem with these cars, often requiring that the expensive ribbon cable be changed out.  But to see any of that, the car has to go up on a lift and be closely inspected for any signs of either water or oil intrusion.

 

Normally, when the valve body starts acting up, the car will code P0730, 0731, 0732, etc.  These are codes indicating the various control solenoid circuits are hung up or blocked, requiring a valve body replacement.  He is correct that a bad valve body will not always code, but they very often do.  Interestingly, on cars we have had to replace the valve bodies on, the oil that came out was absolutely pitiful, black and nasty burnt smelling which required multiple fills and dump flushes before it came out clean: 

 

 

And everything else that came out (the pan, filter, and old valve body) was covered in a coating of black suspended crud:

 

 

And neither of these vehicles had yet to reach the factory recommended service interval.  These things get pretty ugly if the oil is not changed frequently.

[stutzchris]

Thanks again for the advice JFP.  I am grateful for your free sharing of knowledge on this forum.  I will keep will update after I get the work done. 

[ekstroemtj]

I need to agree with JFP

I had similar shifting problems like you. I guess it Happens More often when these cars are used in. City driving or short distance driving.

I did a transmission oil Flush and the car was shifting like new after . I Payed about EUR 600 one year ago.

I recommend to do it. The old oil which came out looks soooooo bad. Cant believe that this black liquid could be healthy for a transmission

[stutzchris]

Here is an update:  After mulling over the Flush or valve body change, my wife and i decided the valve body change would be more expensive and less of a gamble.  Then almost immediately the phone rang and it was The Porsche service department.  The service manager stated the price of the valve bodies had gone up and instead of $2500 the valve body replacement would be $3600.  I chuckled and said you just made my decision easier .... Flush it is ....  If this does not fix the issue I will do the valve body myself since the fluid will be new and what does not come out will be new.  I can do the rest for around $1300 or $1400.  I think it is best to have them do the flush and check for water and such and if there are any updates for my TCU. 

 

Will post updates.

[stutzchris]

Update: 

 

I had the transmission flush completed.  The issues were still there when I picked up the vehicle.  I was a little deflated but half expected that but hoped for a miracle.

 

Once home I hooked up my Durametric and reset the transmission adaptation.  Also I notice the transmission code/setting 12328 was set to Asia.  The prompt said " xx0xx Asia=2; RoW/USA= 0". So I changed that to Row/USA 12028,  Went for a drive .... shifting was much better. It held revs higher and shifted smoother. I did normal driving for a few days and repeated the process.  Over the past week there is a noticeable improvement in the shifting.  The shifting is much much smoother.  The occasional clunk mostly in town when letting off the gas and a low rev up shift happens(previously all the time).  There is the occasional slip from 4-5 on uphill or under load (still much better than before). I am curious if it will continue to improve or deteriorate again.  Time will tell.

 

On the plus side.  I was given 2014 Cayenne to drive as a loaner.  I also asked if I supplied a reman'd valve body to the dealership would they install and the service manager said yes he didn't see why not.  Saving my pennies for a valve body just in case.  Always building my Porsche Service Retirement Account!  Like one guy told me ... "Anyone can buy a Porsche; Maintaining it is the hard part".  Cheers!