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Ok...Ive read all of the posts on this forum and (have been a contributing member since day one of my Cayenne ownership), about the hard shifting from 5-4 and 4-5 with the cayenne S. Mine is an 04S with 94K bought from the dealer with 72K in October (yess I do a ton of driving, but why not do it in style?) Here is the issue: Hard downshifts after cruising in 5th or 6th gear at around 55 mph, when I coast down to say 35 mph and get back on the gas I get a hard clunk (just like everyone else with an 04) as if i just hit a cinder block in the road. my gut is saying trans valve body.

Today I took to the only indy Porsche mechanic in my area (he only works on german autos his lot was filled with BMW's and Mercedes and came highly recommended) and he advised, after witnessing the same symptoms that I have described, that I take it to the dealership and have the Trans control unit and the DME software reprogramed, and then if the issues reoccur, to bring it back to him and then he will proceed with the valve body or full on trans replacement.

ultimatley, here is my question. I have an appt with the dealership on thursday for the reprogram. Am I wasitng time and $ the the software reprogram, or should I just let the dealership diagnose and trust what they have to say? I am a good mechanic and have worked on everything under the sun except a Porsche and am wondering if the TVB is something that is reasonably do-able in the everyday man's garage

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The dealer can confirm your current software number and recommend if it needs upgrading. Chances are that it's a failing valve body which is a straight foreword replacement and not complicated. Recommended to exchange the transmission fluid/filter at the same time.

Well you're under the vehicle inspect the condition of the driveshaft centre brng carrier.

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The software reprogram will probably not fix the issue. The only software update I can recall was for a harsh 1-2 or 2-3 shift. From what I remember, harsh shifts in the higher gears were always valve body issues.

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The dealership called and advised that the software is up to date and there are no fault codes in the trans. They also said that they aren't experiencing a harsh shift in the higher gears. They are calling it a slip and advised that we have the fluid changed. $523.30. And IF that doesn't stop the issue, a shiny new transmission is what they recommend. They are resisting all of my suggestions that it's the valve body, they say they have never experienced this problem before with any other cayennes. WTF? :cursing: I am headed over to take the technician for a drive to show him what i am experiencing

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94K doesn't seem excessive but I would definitely get the fluid & filter changed first. I'm planning on doing mine in the next couple of weeks with 68K.

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I would not waste my money on a fluid/filter change. You will be replacing the fluid when you do the valve body. You can do the filter at that point too. There is a tech bulletin for the harsh 5-4 shift if they look for it. It is not listed with the regular tech bulletins, but it's listed in the workshop manual in the transmission section under "eliminating symptoms", and it states that the fix is to replace the "electrohydraulic control unit", which is Porsche's term for "valve body".

Edited by XR4Tim

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guys having similar problem on my 06, after decelerating or stopping, and then accelerating again I experience loud bang, sometimes a grinding sound then bang. This occurs at 2nd at around 20 kmh.

I went to dealer and recommends TCU change. Will this fix the issue? Please really need help here!!!!

by the way the cardan shaft has been replaced but problem is still on.. . .

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