transmission problem 04 cayenne

clunking in the gearbox sounds like the gear selectors are not aline anymore

2004 is getting up there in years. Have you recently checked or changed the transmission fluid and cleaned the filter screen? Also Tom has a good point with making sure everything holding the transmission in place is tight and also check for worn or damaged rubber mounts.

Go to www.safercar.gov and click on Vehicle Owners Tab and input the year make and model into the search screen. It will pull up 3 Recalls which Porsche will fix for free. The 2 investigations it pulls up might have some merit. Also shows 13 complaints and 39 service bulletins. Not to worry, print them all off on your printer and bring to the Porsche Dealer and have them check your call over for all of them. I did this and the dealer did it for free and fixed all of my recalls. It also scares them a little bit to know you know where to find all this and knowledge is power. They cannot BS you and have to fix it because you have enough ammo to take them to court and win which they won't do. Porsche does the right thing and takes care of its customers in all of my experiences with them.

Transgo 09D / TR60 Shift Kit Fits Rear Wheel Drive Aisin Warner Models - $110 on eBay, a couple of gallons of transmission fluid from Auto Zone, and $500 to my mechanic and problem solved

It is the valve body in the transmission, it's a known problem in the 955 cayennes, the only way to fix it is to install a refurbished valve body with updated valves or the the transgo valve body kit. A refurbished Valve body is usually around $1100 while the transgo kit is only $100. Do your research on both and find the best method for you. You can find the transgo kit and the refurbished valve body on Ebay.