deykamp

1991 Carrera 2 CAB

In a nutshell, it does not seem to want to engage in first gear AND THEN SLAMS INTO GEAR AND IN SECOND IT "SHUDDERS" AND DOES NOT WANT TO UN-ENGAGE. It shifts fine (always had a slight slippage in second).

I WAS TOLD THERE IS ANOTHER FILTER THAT MAY BE PLUGGED BESIDES AND MAIN PAN FILTER.

ANYONE EXPERIENCE THIS ISSUE

It may be a worn solenoid, but why would changing 4-5 qts. of fluid cause this to show up?

I believe the transmission fluid was Dextron III. I don’t think you can get Dextron II anymore. I made sure it was not synthetic.

I believe they have a process where they circulate solvent /fluid through the transmission and it does replace all the transmission fluid. It would also circulate all the contamination through the whole system.

RichieRoo

So, just to be clear, when you say "but why would changing 4-5 qts. of fluid cause this to show up?" - do you mean that the transmission has been working fine and immediately after changing the fluid it began to exhibit the fault?

Dextron III is fine.

Did you do the work yourself? Are you absolutely sure that the correct amount of transmission fluid was replaced?

parsecnc4

How about additional data points, mileage, service history, etc? I recall my BMW 5-series in early 2000 with Steptronic suffering from catastrophic failure after ATF change at an independent shop. Apparently it is not uncommon with BMW’s “lifetime” ATF fluid practice. Hope that is not the case for you since I don’t recall seeing Tiptronic failures from ATF change.

deykamp

Yes, The transmission was serviced at 45,000 and at 92,000.
The transmission worked fine and then when the fluid/filter was changed I had this problem.

The shop said it was probably due to another finer filter being dirty that required pulling the solenoid assembly to clean/change....It seems to do this when the transmission is cold.

RichieRoo

It seems odd that this fault should occur when the fluid is changed.

I hate to question the garages explanations, especially as I am far from
an expert on these matters, but I can only see one ATF filter in the Porsche
PET (943.307.011.02).

I also only found the one mentioned above when I did my ATF change,
which is the one they would have changed. Additionally, to change the
filter they would have remove and cleaned the tip sump, which is where
all the dirt collects (around a magnet). So the filter, ATF and sump should
be free from most contaminants.

If it is a blockage, why would there be a difference in operation between
it being hot or cold?

What does differ between hot and cold is the ATF level, which would say
to me that the level maybe too low. Have a look at the article I wrote
here in the "How To" section. I wrote it because myself and a few other
Rennlisters were having problems getting the ATF to the correct level.
You'll see that the symptoms we experienced were similar to those
exhibited by your car.

Best of luck. Let us know how you get on.