Transmission problem?

[butch199]

I have a 1999 996 with about 53000 miles, tiptronic tranny. My issues is at 2800 rpm when on the highway in 5th gear, i get a surge under acceleratrion almost like the tranny kicks down a gear(from 5 to 4), but the rpm's do not increase and the gear indicator still shows 5th gear, any idea what may be happening? Has any one else had this occur.

Thanks to all in advance

[GranburyChuck]

Hey Butch, can't help with an answer but I am interested in what you find out. I have the exact same problem in my '00 C2 tip. I have 86k miles on it. I had Autobahn Porsche in Fort Worth change the fluid at ~80k miles (I bought the car with 76k miles). They said that the fluid was kind of "gunky" and said that they ran the computer for codes and nothing came up. I am not too sure if they actually ran the codes though. I bought a Durametric scanner and ran the codes myself and nothing showed up, no CEL light either. I thought the problem might be in some kind of electronic throttle reving the engine since it is just a few hundred RPM and not about 1000 RPM for a full downshift to 4th gear. I found through searching on here that someone else has replaced the MAF and that got rid of the problem. Izzy has said that it could be the solenoids in the Tip but you should get a code on the scanner. Kind of perplexing in that this is my daily driver and loads of fun. I am a little anal and this problem just bothers me even though it doesn't seem like a big deal...SO FAR! I'll keep you posted if I find anything and look for your responses to see if you find anything.

[winijr]

I too have a '00 Tip that seems to be kind of shifting a half gear when cruising in fifth and slowly giving a little more gas. I have had the fluid and filter done with negligible improvement. My indie's conversation with a dealer friend indicates that our problem is not unique. Advice after the fluid and filter is to put some miles on it and it should be OK. So far not so good. I have aprox. 55K miles

Any thoughts?

Tom

[Chris_C]

mine does it too, but only if i am at really low revs... i figured it was normal?

Fluid and filter done within the last 1000 miles.

[RFM]

It is a typical ZF tiptronic phenomenon, something with the lock-up program, nothing to worry about never got a mechanical problem with this. It is allied with the driving style.