1998 Boxster Tiptronic Slipping?

[firstgenbird]

Hello everyone, I'm new to the forum and also new to Porsches. Please excuse my bad English. I'm from Turkey and it's nice to be here among you guys.

I've been searching the board for a couple of days, trying to find out if the problem I'm currently having has been covered before. Couldn't find anything relevant, so I thought it's time to post.

My Boxster had been in an accident when I bought it. Previous owner has spinned and crashed the car to a street lamp from behind. The exhaust and left rear axle carrier and shaft was trashed. I found that the impact had made one of the engine mounts break up. I was frustrated thinking I would come across worse internal engine and transmission problems in time. Anyway, I replaced the mechanical parts with good used ones. But the process took a little long, like 2 years :) since I wasn't able to find much time. So the car was sitting in the garage for 2 years, battery disconnected, never started it.

After all the work was done, it was time for ignition, and to my surprise, it lighted up just fine. The engine made a little rattling noise for a couple of seconds, like an empty lifter or such, but it went away quickly. I drove around real slow to let the engine recover from lack of oil just in case. As I came to a complete stop, I had to rev it up to about 2500 rpm to make the car move. No movement until 2000 rpm. But everything else was ok, I had the full gear range working without any problems.

I took it to a transmission shop later, known to be good with ZF's from Audis and VWs, they said the filter might be clogged and so maybe the pump isn't receiving enough initial atf pressure. Sounded logical. They changed the tranny oil and filter. The oil came out pretty dark, but without any significantly bad smell.

The problem was still there, but seemed to be less frequent. So I took it to the dealer, they hooked up the computer thing, don't know what it's called. They found no error codes. The foreman took it for a test drive, and said he feels nothing wrong with the transmission behaviour. Whenever I take a car to a dealer, the problem seems to be gone, making me look paranoid :rolleyes: I described what was happening, and all they said was it sounds strange. The official dealers just love to replace broken parts and that's all they really do here in Turkey.

So .. It's been about 2 weeks now, I've been driving it regularly. Tried a couple of off the line WOT acceleration, shifts down to 1st, no hesitation, the power is there, shifts up just fine, nothing wrong. I'm still having the same problem, but not so frequently as before. Every once in a while I stop at the lights, I have to rev it up to 2000 rpm (sometimes 2500-2700) to make it move, and once it moves, all is fine. It seems to be less frequent when warmed up, but it still occurs. Lately I have also noticed that under 2000 rpm, when I'm cruising constantly at 1800 let's say, the rpm shakes subtly, as if I'm slighltly pressing on the gas pedal back and forth. But after 2500, it's gone.

I feel like it's going away as I drive it more and more. I tend to think that it's because the transmisson sat idle for 2 years, all the atf drained down to the pan, letting things dry out inside, and now it's suffering from pressure leaks because of dried o-rings and such. Nowadays I think it might be a torque conv. problem too. I dont know too much about transmissions, so my guessing might be just silly :lol: Somehow I feel like it will go away in time. Whishful thinking.

I would like to know what you guys think about it. Maybe the torque converter is faulty? Maybe some ATF treatment will help? Maybe it's the beginning of the end? :huh: I don't like expensive electronic european cars because they have always scared me with hard to get problems, but I loved this porsche, there's definetely something enchanting with it. I hope I'm not being foolish, driving it around with this condition.

Thank you all for taking the time to read this. Once again, it's feels good to be on this forum, and I appreciate all your comments.

...I'm attaching some before and after photos, just for personal satisfaction :P

Edited August 8, 2008 by firstgenbird

[El Acura]

Hello.

Maybe only a clog line in the valve body.

Did you tried to raise the ATF oil pressure by selecting drive

and applying full brake and rev the engine.

You will really feel it if the transmission is slipping or not.

BTW Don't push the engine over 3500 rpm because it can damage the torque converter.

Good luck

Edited August 8, 2008 by El Acura

[Beelzy]

I think you are on the right track with the torque converter being the issue.