Tiptronic mysteries

Just out of curiosity, are there actually more than five gears in a 2001 996 Tiptronic trans? I've never owned an automatic prior to my recent purchase of the 996 in my avatar, but I swear I can occasionally feel an ever-so-slight gear change when in 2nd gear at lower RPMs. It feels like there are one or two intermediate gears in there. For instance, when decelerating in second gear, in MANUAL shift mode, just under 3000 RPM I can feel a slight downshift sometimes and another as I get close to 1000 RPM, yet the car will never actually downshift to first gear (I know this is intentional). Just to be clear, I have no concerns with the operation of the tranny. She seems to be doing her job just fine, with no clunks or other odd noises, I'm just the curious type.

Variocam, maybe?

It's probably the torque converter locking the rotor. It does that for fuel efficiency reasons once speed has stabilized after a gear shift, and is unfortunately quite noticeable when it does.

only have 5 in my '02 Tip

the TIP in my 964 acts the same only its 4 speeds. Its normal in 964's.

My 99 Cab does the same thing. I think sjfehr has the right idea. The first couple of times it happened to me I didn't know what it was but then I started attributing it to the torque converter locking up.

Thanks guys. I just gave myself a Torque Converter 101 internet education, and it does seem like what I'm feeling could be the torque converter locking up AND disengaging from lock since I feel the nudge when decelerating.

Yes it is Lock-Up of the Converter. Having had three of these Tips in 964 968 & 996 I can confirm they all act a bit different but the Lock-up is part of the Tranny logic system. The Tip Brain handles the Lock-up differently depending on the 5 programs, so you will sense that transition at different times (RPM) depending on all the factors measured in the Brain. The Tip really is an amazing bit of engineering even thought it is now "old hat" compared to the PDK.

Same thing here...seems like almost a hiccup around low 2k rpms. I at first thought it was a miss.

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Thanks. Can you explain more or provide a link that covers the 5 programs you refer to?

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Yeah, a small hiccup is a good term to describe it.

Keep in mind that were two Tip transmissions installed in the 996. The earlier ZF, like your car and my car has, and the later Daimler/Chrysler unit. They are very different animals, not to mention that the ZF is 40 lbs lighter! I just mention this because the MKII-fitted transmissions behave somewhat differently, including an infinite number of shifting programs as opposed to 5 on the ZF. And I guess the D/C unit has two reverse gears, go figure. Great for fast exits in parking spaces at the mall. LOL

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Thanks for the info. When and why did Porsche change to a Chrysler tranny? I'm not usually a snob about things, but I can't say that I would like having Chrysler anything in my Porsche.

2001 and previous (except turbo) is ZF, old school unit 2002+ it's a mercedes benz trans which was badged daimler chrysler since those companies were one and the same at the time. every 996 turbo, AMG sl55 etc has the same type of w5a , electronic 5spd trans, and is among the best auto transmissions ever made what you are feeling is the torque converter locking up, it's a weird feeling compared to a manual advice on tips, keep that torque converter locked up and drive it in manual mode otherwise it won't be any fun at all

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Thanks htny, I'm enjoying the history lesson. So what make the ZF tranny "old school" and the DC one of the best ever made? Better reliability? Better performance? Better feel? I drive in manual tip mode 90% of the time. I only use "Drive" when I need both hands (ie: coffee in the morning).

The ZF trannys - both 4 speed in the early cars - 968 & 964 where of one type (internally) also used by Audi and others. Was often called one of the most reliable Transmissions in a Porsche. The later TIP S models with 5 speeds where also ZF. The TIP control Logic is in all cases a Porsche / Bosch partnership. All these had 5 Maps for Shift program. As with everything the new models get new technology and the MK II with its larger 3.6 engine benefited with the use of the heavier and stronger BMC unit with a new designed TIP Brain. The Porsche Pano publised lots of details of the early TIP transmission and Porsche published a "Technik" Service Information booklet with more detail - that I referenced on the Lock-Up. Some facts from Technik: (and note this is in the "normal" shift 3 of 5 Program) No lock in 1st gear; 2nd locks at 36mph - opens at 14 - 3rd lock at 40 mph - opens at 22 - --- 4th locks at 45 mph - opens at 30. The other shift programs Open and Close at varied MPH ... Program 5 higher speeds - Program 1 at lower speeds. I am assuming this is similar in the later TIPS but woud vary based on the engine size and Model year changes. The TIP is an inovation that almost every auto maker copied with in a few years.

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Interesting, but I def feel mine lock up at ~26mph in 2nd, every time. Hope mine is working properly.

My Tiptronic is acting in a way that seems odd to me, but might be part of the normal torque converter logic. I guess I have the ZF trans in my '01 C4. As opposed to what several previous posters noted above about issues during deceleration, my issue is during acceleration and upshifts. When I accelerate moderately from 2nd gear and watch the tach rise, there is a point where the RPMs drop several hundred RPM, and then they rise again in relation to speed and the trans shifts to third gear. It is almost like there is a 2.5 gear. This does not happen in any other gear. The trans shifts very well and seems to follow the logic that others describe regarding the other shift programs that depend upon how aggressive I am with the throttle. Anybody else experience their Tip acting this way?

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Well, the mechanic seems certain that this is just the torque converter locking up in a normal fashion. He says this is normal behavior for the trans, but I think he is deducing this from info he read online somewhere. It would be nice to drive another tiptronic car or hear from someone else with a Tiptronic about their experience.

Mine acts a lot like that at moderate acceleration, too. I think you notice it only in 2nd because you're not going fast enough to have it happen in 3rd. If you accelerate harder, the torque converter should not lock up. If you accelerate softer, it should not be so noticeable. In a slush box, the engine's always moving faster than the wheels, that's how it converts torque; when the lockup engages, that rotating momentum in the engine is thrown instantly to the wheels, giving you a bit of a rough shove. I've never watched the tach, might have to tomorrow; but I'd expect the engine to momentarily slow down, just like you described. So: quick fix: BURY YOUR FOOT TO THE FLOOR! Lockup doesn't engage so long as you're in kick-down, and it's more fun, too

Thanks for the response sjfehr. Actually the torque converter locking up is not something that I really can feel. The lockup is pretty soft. Looking at the tach is pretty much the only way to tell its locking up. In fact it was a few months before I noticed it and it was observing the tach that caught my attention. I'll have to try different throttle applications to see if I can get it to lock up in other gears.

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Yes mine does the exact same thing, totally normal according to my indie.

Also have been very pleased with tip. Use manual mode 99% of the time. Had a minor issue diagnosed last year and service manager at dealer agreed the MB five speed is pretty much bulletproof...good to hear.

Thanks for the confirmation RDykmans. CarlosCA, I have heard the same about the durability of these transmissions. I drive most often in manual too especially because of the tendency of the trans to shift up to a higher gear causing engine RPMs to be too low. I have found that for a full acceleration run from a stop, it is best to leave the trans in automatic mode as the shifting logic is very good, and the shifts somehow seem better timed than I can do manually. Other posts have indicated that when tracking the car the automatic mode is also pretty much the best way to go. I haven't tested that yet tho.

The tip is pretty smart about learning your driving style. On the track, it senses kickdown and should automatically go to the most aggressive mapping. It's a little more subtle when you're blending normal low-key daily driving with moments of passion. Teaching the tip with a few manual downshifts when it's not aggressive enough and upshifts when it's more aggressive than you like seems to help it pick a good shift map that fits your driving style.

Mine automatically upshifts the same whether in A or M under hard throttle, agree the shifts seem quicker letting the car do it under hard acceleration. I have not tried A mode on the track yet to see if the downshifting works as advertised when the transmission goes into sport mode. I installed a carnewal RAID wheel with true up/down paddles which makes the tip seem a little more functional. At least now I can hold the wheel properly and shift vs those worthless stock buttons!

Note to HIND ... and all - My post back in 2011 offer some info that was taken from Technik publication for the first Tiptronic. This was the ZF in the 964 and 968 back in 1990 to 1995. So while it give us some insight to the way the system is designed ... much has changes since then. I think all of you are relating normal behavior, and a lot of this can be related to your personal driving style and the terrain as well. Don't forget this system knows when you are going up and down grades and cornering. It reacts to many different inputs. Just remember to say "Thank you Hal" at the end of the drive.

Hi seems like some knowledgeable guys on this forum, well let�s see 😊 C2 2004 ok so my Tiptronic is playing up, I have not really looked into it yet, but I have lost drive a few times, but at the same time I lost the gear indicator on the dash, well the first time it happened I did, on the other occasions my dad had stolen my 996 from his garage and seems to believe the car is shared! 😂 so I wasn�t there to confirm this is the case. so I was thinking possibly electrical issue, but also note someone had noted a low oil level May cause this, and that would tie in with the torque converter trying to lock on while cruising at low throttle, which is the point this has happened. so if the gearbox were to loose power would the drive be lost? Or am I looking at an oil / box issue?

[QUOTE=MetBlk 911;8195052]Thanks htny, I'm enjoying the history lesson. So what make the ZF tranny "old school" and the DC one of the best ever made? Better reliability? Better performance? Better feel? I drive in manual tip mode 90% of the time. I only use "Drive" when I need both hands (ie: coffee in the morning). [ Best understanding for the move to the MB Transmission was that the 996.2 and later Carreras had 3.6 motors and higher torque. And so Porsche, typical over engineering, looked to the future with possible need for that. Another likely reason is they needed that MB Trans for the Turbo so why source Transmissions from Two vendors so the 2002 Carreras got the "Bigger" trans. And as they had a new and more complex control unit (as noted) that same controller went in all models. The ZF unit was and still is very reliable - just "OLD" in the sense of Porsches constant improvement in it quest to make every new model just a bit better & more powerful, faster, etc.

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You might have started a new thread with your issue, it may have attracted more attention. If the lights on the instrument cluster go away I believe the culprit is the switch on the gear selector lever. This gets a lot of use and can get coffee and such spilled onto it as well. If the switch on the gear lever isn't working properly the TCU has no idea what gear the trans should be in. I believe it's quite an expensive part; perhaps a used one might be in order. Or you may be able to open it and clean it. The other electrical problem that can happen with the MB 722.6 is the conductor plate in the transmission itself can go bad, this usually results in throwing codes and the trans going into limp mode. The D and M leds on the cluster flash alternately if the trans goes into limp mode and you have only 2nd and reverse. With any automatic if it's low on fluid it can misbehave. Checking the fluid isn't a cakewalk, you need to get under the car with the engine running and open the upper filler port on the drain pan. The trans temp has to be between 30-40C. The you can add fluid if needed while the engine runs, and close the filler with a new copper washer before you shut the engine off.

Thanks for the reply, could be electrical I guess. I have no issues doing work on the car, Transmission oil will be easy. Other then finding the fitting to fill the oil up. I was thinking either it’s got to be the switch on the side of the box or the oil, so was just looking for direction on which way to go, while changing the oil anyway. plus it’s now developed some more issues now