tiptronic, need some advice, rebuild, possible upgrades

So after my first track experience I posted about sloppy tiptronic behaviour here. https://rennlist.com/forums/996-foru...ck-needed.html The car is 2002 996 C2, so it has the 722.6 Benz automatic transmission. To summarize I had the ATF overheated (fault code found for ATF temperature to high) which made the ECU to limit throttle response. Once off the track the car pulled strong again. After this I went for a ATF fluid flush. Also the torque converter was flushed. Filter change was done too. The old ATF fluid was very dark, almost black. Also it seemed it had an original green colour. Did not smell particulary burned. But have further no reference point to say how bad it looked. Refill was done with Swepco 714 ATF fluid. Before the flush the tiptronic was behaving very reactive. Pulling strong. No jerking when changing gears. Nearly instant downshifts. The only thing I noticed was that it up-shifted a kind of slow under WOT once in 3rd gear and higher. So lets say pulling hard, till almost redline and then shift. It seems it lets the clutch slip longer. Again very difficult for me to judge if this is the normal tiptronic behavior as I do not have a reference experience. After the flush this behavior stayed the same. Car pulls strong. 1st, 2nd and 3rd gear changes are quick when using good throttle action and in higher revs. However when driving in Auto and city traffic, so using just little amounts of throttle the car seems to jerk sometimes when upshifting to 3rd, 1200-1500 rpms and then giving some extra blip of throtllee. above 2000rpm there seems not be any problem. It is best reproducible in 3rd gear. In some cases it happens identically in 2nd. But because the engine spins up faster it seems less prone. In 4th gear it happens too, but not often. From my knowledge I never had this behavior before the flush. Is this jerking related to the tranmission? clutch pack worn out. Torque converter malfunctioning, slipping and then gripping irregularly. Because the overheating situation, the black ATF etc. I am looking at the possibility to get the transmission rebuilt. Maybe also reinforced. Anyone has some experience with that? There are some tranny experts around here who have a lot of experience with the Benz transmissions, such as the 722.6 They can do a normal rebuilt but I also asked them for a possible upgrade-rebuilt. This will then be with better clutch packs, including mod for the 4th gear which seems to be a known weak point. Also upgraded valve body, with the AMG solenoids. The question they raised was the Porsche Transmission Control Unit. It seems they cannot access it. For all the other car brands they have acces and can reflash it. For Porsche they do not know how to acces the TCU. The other solenoids will provide for higher fluid pressure and as such better grip. It will affect shifting and making it more harsh. But as the tiptronic is a very smooth shifter might be that it works fine. The only downside is that they cannot modify the TCU software to fine tune the tranny. I also read somewhere that for the early mk2 996 there is a possible reflash to a more recent version of the TCU which can be done by a Porsche official dealer. Anybody knows more about this?

I'm not sure why you think the 2002 tiptronic needs to be upgraded. The history of this transmission (if properly maintained) is rock solid. It's not a "problem transmission." Swepco 714 ATF might be the problem here or the fluid level might be off. I would only use Porsche OEM or Titan ATF 3353 fluid in this transmission. I own a 2002 911 C2 tiptronic with 120k miles on it and I extensively researched the AFT filter and fluid change before completing the job myself. I found several people who experienced problems with non-OEM ATF fluid. Apparently this transmission is very picky about the ATF fluid used.

I agree with that rock solid reputation. But I have been running the transmission very hot. In such extent that it could have resulted in additional wear and tear on clutches and torque converter. They do not like heat. Overheating creates slipping, which in turns create more heat ... Especially the control board for the valve body is prone for degradation. It is made out of plastic. So overheating is pretty bad for its integrity. I could look into replacing this. And maybe replace the valve body to see if shifting performance is improved. Thanks for the input on the ATF. I will schedule another flush and go for OEM or the Fuchs Titan ATF and see if this brings any improvement. In case I need a rebuild I was curious if there are any people that did some tweaking on the tranny. I know the tuned turbo cars do a lot to handle the extra torque generated. Any input from the Benz tiptronic owners on shifting characteristics in 3rd and 4th when accelerating with WOT and upshifting?

Rock solid but not without failure points. Best point is to drop the pan and see whats in there, if you find clutch material, there....... Valve body is plastic.. as noted. Spring inside valve body can go. If you ran it hot and there is clutch material buildup on the speed sensor, it will create a limp mode issue. Speed sensors can go altogether. Low fluid or incorrect fluid is a no go. Also a major overlooked point is the transmission connector. If it is the benz , then it should be replaced at every Trans service, which is 40k miles. the connector likes to leak and trans fluid leaks back into the control unit. Strong, yes, yes. Able to take power, yes, but they do have their failure points.

Having my own tiptronic fail at 48k miles with zero track use in my ownership and zero in the previous owner, I would now not consider the transmission to be track worthy while also using as a daily driver. One or the other but not both. And if used on the track, factor in frequent failure and replacement because of overheating of the clutches, etc. The trans is certainly capable for street use, but on the track the stresses are completely different. Best to go with a manual trans if you are looking for street and track use from the same car. My opinion.

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Not every Tip owner has the same experience. I have an '02 996 with a Tip used as a semi-daily driver & track toy. It just turned 132,000 miles this weekend at Mid-Ohio. I've been flogging it at DE's and track days for 3 yrs. with no issues whatsoever. And it's the original transmission. The Tip is a very robust, strong and reliable unit.

Mine was not. It had to be replaced @ 100k. input shaft bearing schlit the bed. The tranny has "anomalies" from the very beginning........nothing serious, hard shift once in a while under repeatable conditions, then kaput.

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swepco 714 is regarded as a very good ATF. Can also be found together with porsche's oem 3353 and Fuchs 3353 ATF on pelican parts. if i decide to keep tracking the car i will install an extra atf air/oil cooler. Curious if there are some available kits which fit the 911 without too much extra piping.

There trannys seldom ever have any issues.. I have 3 of them that I can't sell, because there's no demand for them.. I'll take 2K for one if you want to ship it to NL! I have never seen one of these transaxles fail... Never.

Yes, I hear this all the time and I am convinced it is also true. The same tranny was used in the 996TT the 997.1 and 997TT. Ok with some modifications for the gear ratios, newer TCU and mapping and some minor mechanical changes. For the rest it is more or less the same setup. Also the cooling is identical. I checked the part number for ATF cooler on the tranny for all the cars. So having in mind that the TT cars have way more torque to be transferred and a more aggressive torque curve I think we can say the tiptronic transmission is fairly over-dimensioned for the standard NA 996 cars. Nevertheless mine overheated and started slipping upshifting from 3rd to 4th and 4th to 5th. Furthermore the ECU limited the throttle output I think I just have bad luck. Following service records mine was well serviced by the previous owner. Records for fluid and filter change around 25.000 miles ago are there. Valve body got cleaned too. Most probably the tranny was already worn. PO maybe already knew about it, and did not tell its findings when selling. It was not obvious when test driving as it pulled strong and shifted smooth. Maybe the fluid level was too low. Allthough when flushing we found no indication for that. The fluid was toast for sure. So most probably it is a combination of several issues that came together. Existing excessive wear, a half way toast fluid, hot weather and tracking made that it started to overheat causing further damage. However when on the road it still performs good without really jerking, just rather slow upshifts. Thanks for the offer Jake. When time is there I will have a look at the possibility to fly one in from you. You would have any idea about what shipping cost would be. Rebuilding here in NL is fairly cheap (Should be cheap in the US too as there are a lot of 722.6 trannies driving around there!!!) The quotes I got for a standard rebuild to have it as good as new are around 2.5-3K euros + some extra for putting in and out the car. I think it will be more or less the same as shipping one of yours, adding shipment, customs and taxes. Let's wait for the dollar to get cheaper EDIT: I made an estimated calculation: 2000$ for used trannie 600$ for shipment? the total amount under the line for me to be paid including customs and VAT would be then 2900-3000 euros.

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I am planning to do a reflush and put an OEM or similar fluid in. You mentioned the Fuchs Titan 3353. The person who is going to do the job does a lot of Benz trannies on Mercedes. He did not know about the Titan 3353 and if it is compatible for the tiptronic. He proposed instead Titan 5005 (it is the ATF suggested by Fuchs' own website )or the Titan 4134 as an alternative (this one is used for the 722.6 Benz trannies. What is the difference? Probably I will go OEM.

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Is there a specific model number/generation of the trans you are referring to? My 48k failure is the ZF found in the early 996s...mine a 2000 MY built in late 99.