|
Title: Too much slip/surging in TCC control mode? (0 slip at full lockup) (video) Post by: Andrew G. on April 19, 2018, 12:33:07 PM 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.
Some notes I've gathered/observed... 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... Video: https://youtu.be/YWxMOwCJSfc (https://youtu.be/YWxMOwCJSfc) Here are some logs, I don't see anything obvious to me... https://drive.google.com/open?id=1wg...7RFgCxbbymA9oG (https://drive.google.com/open?id=1wg...7RFgCxbbymA9oG) https://drive.google.com/open?id=1oh...stvOixqM3j7INV (https://drive.google.com/open?id=1oh...stvOixqM3j7INV) |