Hello and thank you. New to this forum and to a 2004 cayenne 4.5TT, 3rd owner w/ 100,000. Replacing fluids and filters, saved the tranny(aisin TR-60sn) for last. Removed pan, filter and 7.5L of still good oil. Cleaned pan and magnets. Was able to re-fill 7.5L of aisin type T-IV fluid. Shifts great in all gears, but now has a shudder at W.O.T.. From the T.Q. since it ran fine before. Theories
#1 Cavitation, o-ring not seated on trans filter.
#2 Differences in fluid, didn't put in "Porsche" fluid but trans maker OEM spec.
I'm going to re-do the re-fill and check the o-ring but WHAT FLUID? Thank you, kindly

 

Mobil ATF 3309
or toyota type 4.
Reason it is shuddering is it needs the torque converter flushed when fluid is changed.
Tranny holds 9.6 litres.
usually you change the oil and then flush the torque converter until all is clean.
just completed mine yesterday and went through 10.8 litres.
Now smooth and responsive.