Used search and came up with ideas, but the transmission malfunctions were not describe very well. My problem began as follows.

Saturday took the car out, not even fully warmed, entering a freeway onramp in Drive at maybe ten mph. As I slowly start to increase speed in second gear it suddenly lurches forward and there is a BIG thump...almost as if getting rear ended, but such was not the case.

When I get to the top of the onramp...maybe in third or fourth gear...traffic is slow and heavy. I start to accelerate to move into a faster lane and the same huge lurch and thump again happens. I glance down at the tiptronic indicator lights and they are flashing to let me know something is wrong.

I ease off the freeway as the next exist. The car is in emergency mode and I drive back home on surface streets in what feels like third or fourth gear. Tiptronic warning lights flashing all the way.

I pull into the garage and park. Check under the car, no signs of any fluid leak what so ever. I go inside, read my after market warranty and call the indie dealer and arrange to take the car in first thing Tuesday morning.

I had no previous signs of distress from the transmission. Had it serviced for new fluid and gaskets in February. I drive it aggressively and often in manual mode to keep from lugging the engine. On downshifts I give a very slight blip of the throttle and get engine rev matching.

I went down to the garage later, started and moved the car and had no warning lights or lurches. I reparked and it is still going into the shop on Tuesday and won't be driven until then.

Reading what I could find here, and from driving the car, I don't think it is a "worn transmission" but rather something in the electronic controls, among those being:

Tiptronic supply voltage speed sensors.

TCU or valve body.

Short circuit to B+ ground/between wire or open circuit.

Solenoid on the conductor plate.

All of the above were on threads about tiptronic "lurching." None described anything as sever as what I experienced. I am not a wrench/DIY guy. I would not know how approach any of the above possible causes. I'm going to let the shop find it and fix it but I'm looking for information that I might pass on to them and that I can also educate myself with.

Anyone here have similar experiences and specific solutions or other possible causes? The car is a 2000 cab tiptronic with the later Diameler Chrysler generation tip that allows instant access of manual mode through the steering wheel buttons. Has 48k on the odometer.

Thanks for any information.

 

Sounds like maybe a simple electronic hiccup that was remedied by simply turning the car off and restarting it again. Got my fingers crossed that your indie doesn't find anything too serious. These MB trannies have a bulletproof reputation (quite unlike my Audi D2 S8's!).

 

It is important that when the Tip is serviced the fluid level is correct. This is not just a simple drain and refill. If this was not done correctly this can have the Tip low on fluid. If you can you can check the fluid level and confirm it is ok.

Regarding the behavior, there can be some stored error codes that to a knowledgeable tech can give him a good idea of what is going on. He'll have to get the codes and work from there.

It is possible the behavior was just a "glitch". I really don't like this as an explanation but I have read a number of vehicle road tests in which for some reason the car just started acting up and it got to the point the driver had to just pull over and shut off the engine and wait a while.

While I do not recall coming upon any reports of Porsches doing this it is possible I suppose.

 

Hurdi, you don't have the Mercedes transmission. You have the ZF 5HP19 tiptronic. Emergency run mode is most likely a 3rd gear lock. If simple on/off fixed it, it seems like an electronic problem or can be related to trans fluid level.

 

Thanks everyone for the replies. I had the trans serviced in February (fluid changed, new gaskets and seals, and I'm guessing that if it was fluid level it would have showed up a lot sooner. But I will have everything checked, codes read, and I understand there is a way to check fluid level through the codes.

 

Whatever it turns out to be keep us posted.

 

Had the car just been washed or did you drive through standing water? That can trigger a temporary short and result in limp mode.

 

That is correct Hurdi - you have the first generation ZF as your Carrera is a Mk1.
I'd be worried about the thunk though - it sounds like something mechanical.

Anyway - you need to hook up durametric or something else to see error codes.

The Mercedes 722.9 transmission was put on the 2001 TURBO and 2002+ MkII Carrera models.

 

I'm still looking for Hurdi's post.....?!?!?!?

 

Are Hurdi and John Ireland the same person?

 

Hurry had a really positive post a couple of days ago. I wanted to call it out but was afraid I would break the spell.

 

I get it.

 

The age old rule of "If it happeend once, it will happen again, again and again at a much faster interval". So have a shop that knows these transmissions really well have a good look at it. At this point, it can be anything. Need a proper diagnosis before eve start guessing.

 

No, not in several days. Got up this morning and drove it to the shop. Af first the trans malfunction lights didn't come on but as soon as it hit second gear it did. I'm fairly certain it isn't a short, they put code reader into the plug under the dash. It's either second gear or the TCU. Should know tomorrow.

I talked to a psychic and she thought the car was just confused because it had such an easy first 43k miles and now I was abusing it and making it rev and speed and shift up and down via the buttons. The psychic says it is just like when a woman tells her husband she has a headache. But it's been so long since my wife and I have had headaches I'm not sure what to do.

 

Post up the codes as soon as you have them.

Your dealership may not be the best place to diagnose a transmission issue...it's easier and cheaper (for them, not you) to install a new one than it is to disassemble, diagnose, repair, reassemble, and reinstall a "bad" one. If you feel like you're getting the "it's best to just install a new transmission" treatment - and it's your dime - finding an old-school transmission shop might be worth your while.

This is another one of those times when having a $50 OBD-II code scanner and/or a Bluetooth/Wifi OBD-II adapter and Torque / one of the other apps for your phone would be really helpful, since you'd be able to read (and keep a record of) every diagnostic trouble code without a trip to the mechanic; some codes will clear after additional drive time and that diagnostic data can be lost...