ZF5HP19 too much slip/surging in TCC control mode (0 slip at full lockup)

[drewbz86]

Has anyone ever seen this issue? I just installed a "rebuilt" TC because the old one had lockup clutch seal deterioration and would slip in full lockup (verified once I removed it). I pre-filled the TC with a quart and when everything was back together filled the transmission using the correct procedure. There is absolutely no slip when the TC is locked as observed with my vag com scan tool, but too much slip (up to a few hundred rpm) and surging when in TCC control mode as shown below, even with light/constant throttle. I'm thinking possibly pressure control valve issue? Car is an 01 A6 2.7.

[LakeTahoeQuattr]

I want to hear what others say here but that looks like the TC unlocking and re-locking. I am curious if after some driving the bubbles in the trans will go away and that problem will resolve itself. Yes, I have seen audis fix them selves once or twice haha.

I have seen that similar symptom when coasting downhill in highest gear the revs will dip and come back as if the TC was unlocking and re-locking.

Sorry I dont have an answer but subd

[drewbz86]

Well, at lower RPM the TCM will command partial lock depending on load/driver input. Normally it shouldn't be more than around 128rpm at any given time and definitely wouldn't be noticeable like this is. When the computer detects excessive slip at full lock twice in one drive cycle, it will give up trying to lock the TC until the next drive cycle. I observed this with the previous TC that had a bad seal. The computer doesn't seem to mind excessive slip in partial lock as there are no codes stored in the TCM thus far...

Partial lock (TCC control/regulation) happens in 3rd gear upwards until about 2k RPM/55MPH when full lock is commanded (at mild/moderate throttle of course, else it will open at high throttle). I read about the pressure regulator valve causing excessive wear in the valve body, I don't know if this would be a symptom of that or not...

[JTown77]

my 02 s6 does the exact same thing

[drewbz86]

my 02 s6 does the exact same thing

Does your TC still lock up? My concern is driving like this will burn out the lock up clutch in short time.

[drewbz86]

If it helps I did some logging with VisualME7Logger.

https://drive.google.com/open?id=1wg...7RFgCxbbymA9oG
https://drive.google.com/open?id=1oh...stvOixqM3j7INV

[JTown77]

Does your TC still lock up? My concern is driving like this will burn out the lock up clutch in short time.

Yes, and often remains locked when it should release.

[drewbz86]

Wanted to follow up. I was sent another torque converter and after installing it the issue is resolved!

[JorisRS6]

Wanted to follow up. I was sent another torque converter and after installing it the issue is resolved!

Good to have that solved!



Sent from my iPhone using Audizine

[Fahrvergnugen]

How much fun was the install?

[drewbz86]

How much fun was the install?

You know, this was the third time I've had to pull the motor so I'd say I'm pretty good at it by now haha. As with many of us I find working on stuff in the garage therapeutic.