2012 Panamera 4 970 PDK rattle in 5th and 7th gears

[bcmac]

I have a 2012 Porsche Panamera 4 with 67k miles. Bought it at 34k miles as a certified pre owned  Beautiful car, perfect condition, brilliant road trip machine. We use it for trips around the intermountain west almost exclusively.  However, the PDK unit began acting up on a recent trip: Specifically, there are three symptoms exhibited in during the following conditions: 5th or 7th gear engaged, light to moderate acceleration/throttle (shift mode manual/auto of sport/regular mode do not make a difference) 1) A rattling noise from the transmission, 2) a very slight fore-aft jerking motion, 3) tachometer needle wavers quickly up to 100rpm.

 

These symptoms manifested roughly 500 miles after a PDK oil and filter change.  I used an OE Porsche pan/filter assembly/ OE pan bolts, and Pentosin FFL-3. Followed Porsche's temperature-based  fill and level check procedures. I used a Snap-On Triton D8 scan tool used to monitor fluid temperature.

 

I changed the PDK fluid with Pentosin FFL-3 at 35k miles as well, and had zero issues in the interceding 32K miles. 

 

The local dealer reported that the fluid was 9/10ths of a quart low. Hard to believe as I double-checked the level after a drive cycle. They declined to perform an engine torque adaptation or driving calibration of the PDK. They instead proposed transmission replacement to the tune of $24,500. They said they don't repair PDK transmissions. This from a large dealer with lots of sales and service volume. 

 

The shop foreman suggests that the 6th gear syncro is failing, but no parts are available. Since the PDK has two forward gears engaged at all times for quick shifting- with only one engaged for the power path - 5th a and 7th gear rattles makes sense, to a point. When pushed, the transmission will shift through forward gears flawlessly. 

 

I am at a loss, for I am hesitant to drop $25k on a car that is worth perhaps $32-$36k. 

 

Any Panamera owners out there that have experienced similar issues? 

[JFP in PA]

Welcome to RennTech 

 

I think I know where this may have gone sideways: You may have used the wrong lubricant in the gear box.  The PDK gear box uses Mobilube PTX formula A SAE 75W-90 GL 4.5 gear oil, the Pentosin FFL-3 is for use in the clutch, not the gear box.  If you actually used the Pentosin product in the gear box, it may have caused internal damage:

 

 

From the manual:

PDK transmission oil - approx. 3.12 quarts / 2.95 liters ATF transmission oil Mobilube PTX Formula A (SAE 75W-90) GL 4.5 - change at 120K miles or 12 years.  PDK clutch oil - approx. 5.49 quarts / 5.2 liters Pentosin Gear Oil FFL 3 - change at 60 K miles or 6 years

 

The following procedure is from the 2009 Technik Service information book:

Clutch Oil filling: The correct hydraulic oil level is important for operating the transmission without running into problems. The following preconditions must be met in order to check or correct the oil level:

• Engine must be idling

• Vehicle must be horizontal in both longitudinal and transverse axis

• Hydraulic oil temperature between 86° F. and 104° F. (30° C and 40° C)

• Selector-lever position “P”

• Clutch cooling volume flow must be switched off (using PIWIS Tester in Oil fill mode)

• Retain the described states for approx. 1 minute to allow the oil to settle

• Open screw plug on oil overflow bore and collect emerging oil until only drops of oil are emerging

• Once there is no more oil emerging, top up the clutch fluid until oil emerges at the oil overflow bore

• To avoid damaging the clutches, the procedure must be completed within 5 minutes (PIWIS Tester exits Oil fill mode automatically after 5 minutes) The correct oil level is also important to avoid damaging the gear wheels in the transmission. There is also an overflow bore for this, which is located on the opposite side. The oil level can be checked in the usual way here.

 

The gearbox is filled via the fill port until overflowing.

[bcmac]

To which manual are you referring?

 

I think that you may be referring to the PDK for the Carrera. The unit in the Panamera is unique to the model, in that it does not have separate clutch and gearbox fluid. It takes 9 - 9.5 quarts of FFL-3, as per the Porsche Dealer's technical information. There is only one drain plug and one fill plug on the entire unit. The front differential uses about a half a quart of the 75w90 OE Porsche Oil, or Shell equivalent. 

[JFP in PA]

9 hours ago, bcmac said:

To which manual are you referring?

 

I think that you may be referring to the PDK for the Carrera. The unit in the Panamera is unique to the model, in that it does not have separate clutch and gearbox fluid. It takes 9 - 9.5 quarts of FFL-3, as per the Porsche Dealer's technical information. There is only one drain plug and one fill plug on the entire unit. The front differential uses about a half a quart of the 75w90 OE Porsche Oil, or Shell equivalent. 

 

Further research with ZF on the topic indicates that you are correct:

 

970 generation Panamera PDK transmission info:

ZF is manufacturer of PDK transmission for Porsche

• They make 2 PDK transmissions
  • One for mid & rear engine applications (911, Boxster, etc)
  • Another one specifically made for the Panamera
• Panamera PDK servicing requires two (2) fluids only (as compared to 3 fluids in other PDK car models at Porsche
  • FFL3 fluid - Gearbox & clutches - need about 9 quarts
  • Shell TF0951 - Front final drive - need about 0.4 quarts
• Here is the info dug up from ZF on this topic:
  • "In fact, two separate DCT ranges or 'platforms' have been developed by ZF, both fitted with wet clutches, for use in Porsche's various longitudinal applications. The first is for use in the mid- and rear-engine sports cars (the 911, the Cayman and the Boxster), while a completely different platform has been developed for use in the larger Panamera. For each platform, two different torque options are available, with the 500N.m versions using an 'ND2015' clutch pack, and the 780N.m versions using an 'ND2216' clutch pack, both supplied by ZF Sachs.......
  • In terms of the oil circuit itself, two completely different approaches have been employed for the two platforms.
    • Non Panamera models: The 7DT45 and 7DT70 have two oil circuits, and hence two different oils; the first is Pentosin FFL-3 for the clutch and hydraulics, and the second is ExxonMobil Mobilube PTX 75W-90 for the gear-set and bevel gear. The oil levels have been kept as low as possible, to reduce churning losses for those moving parts that are immersed in oil.
    • Panamera: Conversely, the 7DT75 has a single oil circuit and a dry sump (to minimize churning losses), with an 'active lubrication system' to feed oil to each gear-set and clutch. This version uses only the Pentosin FFL-3 lubricant, which was developed exclusively for the ZF DCTs. One of the main reasons for using a single oil circuit is that clutch cooling is required at both ends of the transmission, for the main dual-clutch module and for the hang-on clutch used in the four-wheel-drive variant. This would have presented significant sealing complications had multiple circuits been chosen."

Bottom line:

What this means is that the Panamera PDK uses transmission design which uses one fluid compartment for the gearbox and the clutches, and another separate compartment for the final drive. Two fluids total.

[Silver_TT]

My Audi Q5 has the ZF 8HP and that’s correct, there is a fluid for the gearbox and a separate different oil for the transfer case.