CDinSing

Guys,
Just purchased a 2005 Boxster S (55k miles) with Tip for my wife. The car runs fine but at 40mph it will shift into 5th and then at a steady cruise and steady gas pedal input the engine will fluctuate +/-200rpm like the tip wants to shift to 4th but doesn't or the torque converter is locking and unlocking. It repeats every 3-4 secs. At highway speeds the trans acts fine. This only happens around town at 2000 rpm.

My local tech and Porsche dealer have never seen this problem. I was told it may be just in need of a fluid/ filter change. But, I am concerned it could become a bigger problem if I keep the car. Before I send this car back to the dealer does anyone have experience with this?

Thx,
CDinSing

Macster

Well, it would have been better had you ID'd this behavior before you bought the car and had this behavior addressed of as a precondition to you accepting the car. You would have lots more leverage then. I mention this not to rub salt in your wound but for the benefit of others. A proper test drive of a used car is very very important.

My advice would be if you could get the dealer/seller to take back the car do so.

While a fluid change may address the behavior it may not and a Tip rebuild is not cheap. 'course, if you have some way of having the seller cover this then that's a different story.

If you are so to speak stuck with the car, then have the Tip fluid changed. There have been reports of a fluid change making things all better.

I have to add though I have been told that often it seems when a Tip is manifesting abnormal behavior a fluid change doesn't help at least for long and in fact can appear to accelerate the Tip's decline. I suspect what really happens is the thing is just too far gone and the fluid change had really nothing to do with the Tip going bad. It would have gone bad anyhow.

The answer to this is to have the Tip fluid changed *before* the Tip starts to act up. So many Tip owners take the Tip for granted. It is a very nice transmission and will give one years of trouble free service but regular fluid/filter services as the miles accumulate won't go amiss. (No need to get all crazy with this but cutting the scheduled fluid change by 1/3rd or if one wants to get just a little crazy to even to one half of the scheduled miles is sufficient. Say if the fluid change is scheduled at 90K miles (just a number) then doing it at 60K miles or even 45K miles is about all the crazy one needs to get with Tip fluid.)

'course your car just has 55K miles. So technically the Tip fluid is not really due even if one subscribes to the aggressive fluid change schedule I offered above. It is the relatively low miles on the car in question that sort of makes me believe, make that fear, that a fluid change might not help, or if it does help, not for long.

CDinSing

Agree with your advice. I have purchased 4 used Porsches and all had PPIs. There were a few that failed a PPI and I walked away. This is my first sanity lapse. In my defense I had a 48 hour return clock and my Indy was three hours drive from the car. The car was keeper aside from the the tip problem. The dealer gave me the option to return the car and unwind the deal or they would have it fixed at their cost. I chose to unwind it but still in the process.

sjfehr

I had a similar issue with my 2004 986S; turned out to be a vacuum leak from a loose vacuum hose connector on the intake manifold; was a small vacuum leak, but the unmetered air caused the engine to hunt a bit when the engine was bogged down at low rpm in a high gear. I found it was fairly easy to troubleshoot by wrapping suspect connectors with electrical tape and seeing if it stopped.

Sonderwunsch

OP, I'm sorry to be the bearer of bad tidings....
I had this same issue with my last Boxster S, also a 2005 tiptronic. The fix was a transmission replacement.

CDinSing

Thanks for the replies. This is definitely a tip issue, it is thinking about shifting then not doing it. I was hoping a simple fluid flush would fix it, but that is more than likely not the case.
No worries, they are unwinding the deal and picking up the car. My wife is upset because she loved the car, but based on the range of possible solutions and cost, I am not willing to take the risk.

Back to the hunt.

Macster

There are of course less expensive to address explanations for the behavior, but there is the real risk the car could have required some serious money to put things right.

So, while it is hard especially given how your dear wife loved the car, returning the car -- especially since this involved no real knock down drag out fight to do -- was the best course of action.

You adhered to the 1st rule of buying a used car. There is always another car.

Ricarr

Any further comments on this issue? I am having a similar problem with a 2007 Cayman with the tip trans. Did the trans service but no help. My guy now wants to have the valve body rebuilt as he believes it is a fluid pressure issue (when you are aggressive on the gas, doesn't seem to do it and the more aggressive, the higher pressure, according to him)

Kevin 450

Did this problem get resolved I have the same issue

Ricarr

my guy had the valve body rebuilt, didn’t totally fix the problem....we then replaced the torque converter and it is perfect and has been for a while....was able to inspect the ims at the same time and all was good there

Kevin 450

Hi Ricarr thanks for your reply I’m going to do the obvious diy things first clean throttle body, maf etc, if not successful then go down your route good to get feedback on how you resolved the issue thanks again.
the one thing I have noticed that it seems temp sensitive from cold it does not to it till it’s passed 65 on the temp gauge
kevin450

nordschleife666

I have recently experienced with the same problem, with rpm surges about 200rpm every 2-3 seconds when I hold steady the throttle at cruising within the rpm range of 1600-2500. I went to garage for an oil change and check on this, they found two vacuum pipes broken. After fixing them, it seems the problem has gone now.