Loud clunk during hard acceleration/downshift
#1
Loud clunk during hard acceleration/downshift
I've searched without much luck but here's my problem with my 2006 S. I was driving home last night and went to pass someone. As the transmission downshifted from 6th to 5th, there was a very loud "clunk." It startled me enough that I immediately let off the gas so I don't know if it would have clunked several times. The closest description I can come up with is that it sounded like a gear was missing a tooth somewhere and it clunked when it grabbed the next tooth. The transmission doesn't seem to slip but my wife then said "Yeh, it's made that noise four or five times"......don't know when she was going to tell me about that!
Anyone ever experienced this before or have any suggestions on where to look or start?
Thanks!
Anyone ever experienced this before or have any suggestions on where to look or start?
Thanks!
#2
Rocky Mountain High
Rennlist Member
Rennlist Member
It sounds to me like you have a failing transmission valve body. This is a fairly common issue on Gen 1 Cayennes. If you have it replaced, your transmission should be fine.
#3
Race Director
Another suggestion would be to check the engine stabilizer bar under the hood, right side of the engine. Check the bushings on both the engine side and the frame/body side for rips and or tears.
#7
Rennlist Member
Welcome to the valve body clunk club. It's annoying. I can avoid it every time if I let off the gas and manually shift. It's something on my list. You can be scrappy and do it for less money as long as the TCU doesn't have to be replaced as well.
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#8
Ouch.
I've noticed this recently when manually downshifting from 5th to 4th or 4th to 3rd. How is the definitive diagnosis made? Does it throw a fault code?
--Bob (original owner - '04 CS - 61k miles)
I've noticed this recently when manually downshifting from 5th to 4th or 4th to 3rd. How is the definitive diagnosis made? Does it throw a fault code?
--Bob (original owner - '04 CS - 61k miles)
Last edited by rbaron; 06-15-2013 at 07:52 PM. Reason: clarity
#11
Update: I had the car in to the dealer for the 60,000 mile service last week - as well as replacement of failed coolant pipes - and asked them to check the transmission for clunks.
The complaint: "Occasional transmission has a clunking noise when downshifting. Ck & Adv."
The report: "Technician found engine torque mounts loose, re-torqued mount, no other problems noticed and no faults in system."
The complaint: "Occasional transmission has a clunking noise when downshifting. Ck & Adv."
The report: "Technician found engine torque mounts loose, re-torqued mount, no other problems noticed and no faults in system."
#12
If it just started then it would be very intermittent and difficult to reproduce so it's possible that it was as simple as retorquing but I wouldn't be surprised if it came back, especially with your description, in which case... Transmission valve body, it'll run you around $2K for parts and labor including the TCU which IS required if using the current parts. There are remanufacturers that sell the old VB's for less but I know nothing about the quality or process. I had mine done right about a year ago and no issues since. Good luck.
Last edited by Cuba; 08-02-2013 at 04:06 PM.
#13
Does anyone have any relevant knowledge on this subject (other than 'it is - or soon will be - the valve body')?
Thanks,
--Bob
#14
Drifting
On my 09 GTS during the first 15k kms of the 70k kms that I owned the transmission clunked (well it actually felt like the transmission was going to join me in the cabin) twice. No resolution and no repetition.