Has my Tiptronic gone south or not quite?

[PMc4S]

First of all, I wish everyone an enjoyable 4th of July holiday weekend :D

Was hoping I wouldn't be one of the unlucky ones, but my hopes seem to have gone south along with my transmission.

The single-owner 2003 C4S I bought at the end of last year came with a complete service history. The transmission had been replaced with a new unit under warranty at 32K due to an "internal problem". I was OK with that since I figured the odds of another failure on a new transmission were slim.

Not quite I guess.

Third gear started to slip last week with 63K on the odometer - which signalled bigger problems to follow. Threw a CEL and so I parked it. By the time I drove it to the dealer Wednesday, it was having difficulty engaging drive and couldn't get past third gear whether in auto or manual mode. However, coming home from the dealer it was almost 100% OK (?). The code thrown was a P0701 which is "transmission slips/implausible gear" and the dealer's diagnosis was terminal: transmission has an internal leak and requires replacement. The ATF fluid & filter are original to the replacement transmission.

Before I sink funds into a rebuilt unit (used transmissions are not easy to find thus far), should I try changing the fuild & filter using the DIY method posted here, in hopes that might bring it back? I have read that clogged filter can result in slippage, hesitation, and gear engagement issues. Or is this thing a goner for sure with the symptoms I described above?

Any & all insight appreciated before I dip hard into the wallet - but please refrain from "shoulda gone with CPO" comments...live & learn. Thanks!

Paul

[htny]

I'm not an expert on this unit, but before you do anything, check to see when the replacement unit was installed, it should carry a 2 year warranty from the date of install.

I have a little experience fixing the actual mercedes unit but not in the Porsche. I can tell you that they rarely go bad do to internal issues (it happens, but...), so you may want to check the electronic transmission control unit, and the wiring. You should be able to find a resistance/testing diagram for all of the pins on the harness.

It could be something as small as a little ATF getting into the ETC, or a faulty solenoid, and you should be able to test each shift solenoid from the harness as well (electrically, not mechanically)

It should be noted that you cannot reset transmission codes in these transmissions without a dealer tool, it's a different module than can be accesse with the code readers.

you can examine the fluid in the pan to see how much metal is shaved off, an excess would indicate excessive internal wear. changing fluid probably won't help you at all.

[PMc4S]

Thanks for your advice Hans. The replacement was installed back in 2005 so I'm SOL for warranty.

I would rather not get into draining & changing the fluid if the transmission will still have to be serviced afterwards. From everything I've read and the possibility of an internal leak, I'm going to guess I have a bad valve. My next step is to find another indie mechanic who knows Tiptronics to have a look - hopefully I can squeak out of this without needing a rebuild or replacement.

Izzy, are you able to diagnose with the info I shared?

[htny]

just to update everyone, we've been talking abou this on rennlist too, here's the gist:

In my personal experience, the MB 722.6 series 5 speed electronically controlled transmissions are near bulletproof mechanically in most applications (although I haven't dug into the specifics of the configuration in the turbo TipS in the 3.6 cars). You may need a solenoid once in a blue moon, but most of the problems happen to be electronic or electrical in nature, as you might expect. I have had 3 and still have 2 MBs with this trans and one 996, and have never had any real trouble.

The problem is that, just like M96 motors, there is very little market for rebuilding cores, so nobody knows how to work on them, and will recommend R&R for the smallest issues. Changing the fluid is one of the most often prescribed knee-jerks ahead of replacement, but more often than not will cause more problems than it fixes. They rarely leak, and when they do it's almost always from very well documented places, however maintaining appropriate fluid levels is critical to longevity and repairing leaks when you see them is not only simple, it's a must.

90% of the problems have to do with damage to wiring, pins, or the ETC itself, either from impact, broken mounts, or from leaking trans fluid wicking up into the transmission control module. The electrical test programs for this series of transmissions is relatively uniform, and if anyone ever needs them I can send them to you.

They are pretty easy to troubleshoot and repair electrically and electronically, but if you do lose a seal or clutch pack you're SOL, R&R. It's important to note that in all MBs and other cars with these transmissions, you CANNOT reset them utilizing a generic ODB tool. You can reset the trans code that's in the ODB computer, but it will not reset the ETC, which you will need to manufacturer's tools to access and clear after making an electrical or electronic repair.

__________________

Quote:

Originally Posted by mtl911sc

Hans, do you know if the control module is available as a replacement part if it has been damaged by leaking fluid? The dealer told me I have some sort of internal leak but my indy mechanic hasn't taken a look yet.

__________________

Once again, my experience is not with the TipS application, but I would imagine you could order one from Porsche. The exterior enclosure of the ETC may vary. Call up Sunset or Suncoast and give them your VIN, they'll give you the part number and price if it's available here or from Germany. FYI, the likely number is (1) 996 618 180 07 CONTROL UNIT TIPTRONIC SEE TECHNICAL INFORMATION GR. 3 , NR. 6/02 02 1 M 249 $1753.69 but you really need to speak with a dealer about your specific car.

Before you do that though, inspect the control module for evidence of contamination, spots of fluid etc. If clean and throwing no trans codes to the OBD port, you probably don't have an issue a the ETC. however if you do see evidence and want to repair fluid damage it's just a matter of opening, cleaning with Electronic Cleaner, air drying with a fan (no heat guns!) and reinstalling. Then you have to stop the leak at the source, and if it's in the ETC then the leak is 99.99% from a collar down by the pan where the cable harness plugs into the shift control module, and an updated part should be available for very cheap.

Most 722.6 trans don't come with a dipstick for fluid, but a tool can be ordered from anybody, MB, Chrysler, assuming Porsche etc. I've seen tools from MB and Chrysler and they are the same. Looks like a long piece of metal with a big red handle (shocking I know) and does NOT insert all the way into the filler tube. To be safe order one from porsche if they sell. Make sure you measure the trans fluid level when at operating temperature, car running, shifter in neutral or park. Use an infrared thermometer to measure the temperature, and read the level off the tool.

Some final notes, in my research tonight I can confirm that all the 02+ cars are 722.6 MB transmissions, however the part numbers are different (as they should be, 4wd / 2wd). The C2 should have an A96.10 and the C4 should have an A96.35. The 01 turbo had A96.50 but it's unclear whether or not the 02+ turbos are A96.50s or 35s. The A96.50 almost had to be a 722.6 W5A 580 as 580 Nm is from my memory the highest capacity AWD trans MB made back then and the only one capable of handling the turbo's torque rating. This also means that the TipS in the Carreras either doesn't have the same torque rating as the turbo or is otherwise differently configured, maybe different gearing. Adrian or Loren should be able to confirm for you. The below list seems to confirm my reading of this however the number of gears seems to include reverse! If anyone has an 02+ shop manual they want to email me a link to, I can confirm how closely the shift plate resembles the ones I've seen for this trans before .

A96 Porsche Automatic Getriebe für Typ 911 Carrera (996)

A96/00 6 Gang Automatic Getriebe für Typ 911 Carrera (996)

A96/10 6 Gang Automatic Getriebe für Typ 911 Carrera (996) ab 2002

A96/35 6 Gang Automatic Getriebe für Typ 911 Carrera (996) ab 2002

A96/50 6 Gang Automatic Getriebe für Typ 911 Turbo (996) ab 2002

What work did the dealer do to determine that there was an internal leak?

Is the trans giving you any codes at the OBD port? If so please post.

__________________

Quote:

Originally Posted by mtl911sc

The dealer was vague - reading directly from my invoice: "verified fluid level, according to procedure there is an internal leak in the transmission. Transmission needs to be changed." So I assume the tech was going by the diagnostic in the service manual, although no specific location of the leak was specified.

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They only accounted for code P0701 "Transmission slips" but I believe that's an engine code and not from the Tiptronic unit itself.

you wouldn't happen to be Paul, PMc4S on renntech would you?

As I understand it, P0701 at OBD port is Transmission Control System, not a ratio/gear code (those are generally P073x), and should be accompanied by sub codes. The same codes are thrown by the ETC to the OBD, they just can't be reset by an OBD reader, need a real tool for that. you need to go out and spend 50 bucks on a code reader, or a couple hundred for a durametric, and drill down on the codes. I'm no sure whether Durametric resets tiptronic codes yet, they were still working on this last time I checked, call them, great people. Knowledge is definitely power here, knowing the exact information from the port could mean the difference between a 100 dollar repair and a $10K nightmare.

[msanati1]

Has,

My name is Mike. I really need your help with this one

I have a 1999 C2-Cab with Tiptronic. It has 53000 Milles.

About a month ago the transmission start slipping and making clonking noise shifting 2nd to 3^rd.

And Check Engine light came on.

Toke it to local dealer they pulled the code and it had two fault code:

--Code 72 Gear sel. Monitor, 2^nd Gear………….OBD II ..P0732

--Code 70 Solenoid valve – Torque Conv.……..OBD II ..P0740

The dealer wants to replace the transmission and the control unit for close to $17,000.

What do you suggest?

Thanks for your help.

[Loren]

Has,

My name is Mike. I really need your help with this one

I have a 1999 C2-Cab with Tiptronic. It has 53000 Milles.

About a month ago the transmission start slipping and making clonking noise shifting 2nd to 3^rd.

And Check Engine light came on.

Toke it to local dealer they pulled the code and it had two fault code:

--Code 72 Gear sel. Monitor, 2^nd Gear………….OBD II ..P0732

--Code 70 Solenoid valve – Torque Conv.……..OBD II ..P0740

The dealer wants to replace the transmission and the control unit for close to $17,000.

What do you suggest?

Thanks for your help.

:welcome:

P0732 Gear monitoring, 2nd gear - signal implausible

Possible causes:

- ATF level not OK

- Solenoid valves

- Valve chamber

- Transmission

P0740 Fault, torque converter clutch - present

Possible causes:

ATF supply

- Torque converter

- Pressure regulator 4 (hydraulic)

- Electrical triggering to pressure regulator 4

- Hydraulic control unit

Sure looks to me like you should start by making sure the ATF is at the proper level.

Then run the Tiptronics tests with a Porsche PST2 or PIWIS tester.

[Richard Hamilton]

Both could be caused by incorrect ATF level. There is a lot more which should be considered before replacing the transmission. A solenoid could be causing P0732, and the Torque converter clutch could be the cause of P0740. The common factor on the diagnosis sheets is the ATF level though.

Beaten to it by Loren, as usual!

Edited February 27, 2010 by Richard Hamilton