Hello all,
I've been having problems with my ZF8 since I bought my car and am worried I may be in for a new transmission. If you're wondering "What the hell is the -55 variant?" well I actually have a C7 2012 Audi A6 with the 3.0T, but the Dodge forum seems much more active along with a specific subforum for the ZF8 so I decided to post here.
I bought the car with around 110,000 miles this past May after my last Audi was unfortunately totaled, with no record of tranny fluid being performed (Audi claims tranny fluid is "lifetime"). When accelerating from a stop or accelerating after slowing down and the TC disengaging, the car accelerates but RPMs will momentarily drop once the torque converter decides to lock up. When I am in manual mode, if I try shifting while the torque converter is still slipping, the revs will drop ever so slightly until the torque converter finally locks up. If I stop accelerating while the TC is slipping the RPMs instantly drop. The TC finally locks up after about 2nd or 3rd gear and while slipping, I can definitely feel I am fighting the TC. When slowing down I can feel the TC disengage, though not harshly.
Along with this when shifting from 5th to 6th, I can hear an audible "click" sound from the transmission outside along with a very slight thump, though nothing aggressive nor does the car lurch. When doing a launch control/brake boost, the car will short shift from 1st to 2nd (I assume due to the TC slipping so much), and once I reach the top of my RPMs, the car will refuse to shift into 3rd until I let off the gas.
Finally when downshifting from 3rd to 2nd around 1,700 - 2,300 RPM (when I usually hit the downshift paddle), the car will lurch a little bit and hesitate where the car jerks back and forth until the shift is complete. All other downshifts, especially 5th to 4th, are lightning-quick. Upshifts under heavy throttle are also super fast, with no slippage I can feel.
I am wondering if anyone who works with ZF8s has seen these problems before. If I am looking at the clutches in the TC being bad along with a bad solenoid in the mechatronics unit, I feel like $350 for a tranny with 60k - 75k miles (right by ZFs recommended fluid change interval) is much cheaper than a rebuild for my transmission.
I'm a tech at the dealership and whenever I drive A4, A5, A6, or A7 with the ZF8 it is noticeably smoother with TC lockup being imperceptible, I'm never fighting the TC when accelerating, and the downshifts seem to be ever-so-slightly faster than my fast downshifts, along with the 3rd to 2nd gear lurch not being present. I performed a fluid drain and fill with new filter and that didn't help the issue. I also tuned the ECU and TCU with 034 motorsports hoping that the tune would increase clutch pressures to the clutch packs but with no luck.
Any help is appreciated. Thank you!
Here are some videos demonstrating my issues:
(Slow TC lockup at 0:13, 0:25, 0:42, and 0:56, with 0:25 and 0:42 being what I experience the most)
(Only good launch control I had, with momentary dip being me taking foot off throttle since I forgot tune had ignition-cut launch control)
(Once I launch, it short shifts into 2nd due to TC slip I assume and then doesn't shift into 3rd until I let off the gas. Sorry for not getting good view of RPMs)
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Originally Posted by DodgeBoy_8HP
