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I'm convinced it's nothing more than the locking differential clutch packs 'chattering', as I've experience numerous times in years past with various GM LSDs in F-bodies and Z06 Corvettes I've owned. Sounds and 'feels' identical. In GM's case, it's completely cured with the addition of the correct amount of GM's limited slip additive. I'm not certain if there's something that would work in Porsche's unit, but I'm sure the fluid for the PTV+ diffs has something in it that accounts for that (or is supposed to account for that anyway). I
The GM fluid worked wonderfully in an '87 BMW 535i with LSD that I owned.. about half the bottle did the trick.
Every 958 I've driven with the PTV+ option (including mine) has made that sound on occasion with tight, slow left turns. Mine has the new revised TC along with the other updated bits, and some time ago had the WD-31 campaign fix applied as well. It still does it on occasion though. I'm convinced it's nothing more than the locking differential clutch packs 'chattering', as I've experience numerous times in years past with various GM LSDs in F-bodies and Z06 Corvettes I've owned. Sounds and 'feels' identical. In GM's case, it's completely cured with the addition of the correct amount of GM's limited slip additive. I'm not certain if there's something that would work in Porsche's unit, but I'm sure the fluid for the PTV+ diffs has something in it that accounts for that (or is supposed to account for that anyway). I just really don't worry about it much anymore.
It's a very different symptom from a failing TC.
misery loves company then. Thanks for writing this up. This is exactly what I am experiencing,... although I would love to hear why there is a connection to PTV+,... given that all PTV really does is apply braking pressure to the inside wheels which are experiencing less traction. So how does that come into play when we hear & feel this noise on slow tight left hand turns? I just blame the LSD & not really the PTV.
Anyway,... I have been wondering if I could suggest to my dealership that they entertain an additive to the Diff oil.
Porsche Magic stuff for PTV differential. ($35 a bottle, requires 2 bottles total for front and rear. 1.3 liter rear and .5 liter front)
I'll report back tomorrow when i have a chance of changing.
For the record: 2011 Cayenne S, 73k miles, PTV Plus, PDCC. I did the TC fluid change, my car has never had a TC issue. Flushed therefore it does not become an issue. I do have rear noise what sounds to me like traction control kicking in during left and right hand turns from stop lights(appears to come only from rear differential). I'm hoping by doing this fluid change, it will minimize the "traction control" feel kicking in.
Update: For those with PTv Plus and PDCC that have the "crunching" / "traction control" noise coming from the rear differential. After changing the fluid - 90% + noise gone. I have only done about 30 miles of driving.
Recap: My car has had the "flash update" campaign perform, still had the noise. Purchased Porsche OEM fluid from picture aboive (part # 000043300037 ) . 1,3 liter rear and .5 liter up front.
This is exactly what I am experiencing,... although I would love to hear why there is a connection to PTV+,... given that all PTV really does is apply braking pressure to the inside wheels which are experiencing less traction.
=Steve
Hi Steve. PTV+ equipped vehicles have a completely different rear differential unit versus the standard one installed in non-PTV Cayennes. The PTV+ system uses an electronic fully locking unit. So it's not only the automated braking pressures you mentioned as part of the PTV+ system, but different hardware as well.
Update: For those with PTv Plus and PDCC that have the "crunching" / "traction control" noise coming from the rear differential. After changing the fluid - 90% + noise gone. I have only done about 30 miles of driving.
Recap: My car has had the "flash update" campaign perform, still had the noise. Purchased Porsche OEM fluid from picture aboive (part # 000043300037 ) . 1,3 liter rear and .5 liter up front.
Good to hear that. Next time my vehicle's at the dealer for an oil change, I think I'll ask them to change the PTV+ rear diff fluid as well and see if that eases the noise a bit, although mine doesn't do it too much anyway. I suspect like the GM LSD's, that fluid really does require replacement occasionally, despite what the service schedule states.
And as you noted, the WD-31 "flash update" campaign applied to mine as well some time ago, really does nothing for the PTV rear diff noise we've been discussing. I'm sure it serves some other purpose though.
Thanks CarGuy for that explanation. I did not know we had a different PTV differential.
Hey Don,... while I'm thinking about this,... do we want to take this discussion off-line from this TC thread? Although it is possible that Cayenne owners are getting confused on which sounds are coming from where,... and whether they should suspect their TC -vs- Differentials.....
... plus this may only be a PTV differential issue. I do not yet recall any non-PTV owners chiming in to say they are experiencing the same crunching from the rear or not. Your call on keeping this discussion here, or creating a new one.
Thanks F1 for the report out on positive results from the SAF Carbon Mod 300.37 oil.
Since it was under warranty - I guess a change of fluid wasn't tried? New isn't bad if it didn't cost you anything.
It went in for a sevice and they said it needed a new one, as it's under warranty with no excess (so all it meant was a couple of extra days without the car) I didn't argue!
I will, probably in about a week make a new sticky for PTV issues and move the posts here over to it. I want to do that at a real computer - right now I'm using an Asus Transformer, my travel, read-email computer, and the screen size and mouse aren't really conducive to doing it. Great suggestion, and having the thread separate from the TC thread will give it better exposure.
Just purchased a '14 S (see other threads) with 45K miles a few weeks back...it's not symptomatic (no noise or turning issues), but since it's a CPO car, I begged the dealership to do the TC fluid swap while it's in for other minor work. They said yes, so I'm very happy.
Just purchased a '14 S (see other threads) with 45K miles a few weeks back...it's not symptomatic (no noise or turning issues), but since it's a CPO car, I begged the dealership to do the TC fluid swap while it's in for other minor work. They said yes, so I'm very happy.
TXCOMT
Make sure they are using the latest Porsche TC fluid 000-043-305-63. Most dealers don't keep it in stock and will have to order it. When I had the TC fluid changed I provided the Porsche fluid to my dealer since they didn't stock it.
Make sure they are using the latest Porsche TC fluid 000-043-305-63. Most dealers don't keep it in stock and will have to order it. When I had the TC fluid changed I provided the Porsche fluid to my dealer since they didn't stock it.
Good to know and thanks for the heads up! BTW, I was planning to change it once again with the Ravenol product after a few weeks, but this is still great advice.
^^ same scenario for Differential fluid. They do not stock it as they have it "by the drum in the back" i was told.
Also, they do not ship fluids. Pickup only.
