Weird A4 shifting problem
03-08-2008, 12:01 PM
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Weird A4 shifting problem I recently replaced the gears from 2.73 to 3.73 on my 2000 TA. I had the shift points updated by one of the best tuners on the east coast, who did a full street tune. Overall, I am very happy, but..........
Every once a while, it will shift hard..real hard. For example, I went to work yesterday. No issue. Went out to lunch. No issue. Drove home, now it's shifting hard. It doesn't seem repeatable, and I haven't found a way to replicate it so I can take it to my tuner to diagnose.
Here's what it does. Most notible in the 1-2 up-shift. With very little throttle, it will "jerk" into second. This shakes the whole car. I've been in complete stop and go traffic and have momentarily spun the tires with barely any throttle. It almost seems like the car is running lean? If I shut off ignition and turn right back on, it still behaves this way. But if I go home and start it the following day, everything is fine. But sometimes it has also done this after sitting cold after the entire night. Just not repeatable. It does seem that sometimes going WOT causes it. Sometimes, just on it's own.
Any ideas what's going on?
Every once a while, it will shift hard..real hard. For example, I went to work yesterday. No issue. Went out to lunch. No issue. Drove home, now it's shifting hard. It doesn't seem repeatable, and I haven't found a way to replicate it so I can take it to my tuner to diagnose.
Here's what it does. Most notible in the 1-2 up-shift. With very little throttle, it will "jerk" into second. This shakes the whole car. I've been in complete stop and go traffic and have momentarily spun the tires with barely any throttle. It almost seems like the car is running lean? If I shut off ignition and turn right back on, it still behaves this way. But if I go home and start it the following day, everything is fine. But sometimes it has also done this after sitting cold after the entire night. Just not repeatable. It does seem that sometimes going WOT causes it. Sometimes, just on it's own.
Any ideas what's going on?
03-08-2008, 02:40 PM
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After further searching, I came across this.
https://ls1tech.com/forums/showthrea...=shifting+hard
If this is the problem, what can be done to fix it?
https://ls1tech.com/forums/showthrea...=shifting+hard
If this is the problem, what can be done to fix it?
03-08-2008, 02:59 PM
#3
See if your Tuner can data log it. Let's see why the pressure is being commanded to go high. There will be a corresponding event such as irregular MAF readings for example.
g
g
03-09-2008, 07:29 PM
#5
If this is only on the 1-2 shift I would suspect a sticky 1-2 accumulator valve and sleeve. We see it all the time in valve bodies that we fully disassemble. What can happen is either very soft shift or very hard shift depending on where the valve sticks. As mentioned above this could be a tuning problem but if nothing is found there you might consider having the valve body serviced. Vince
03-10-2008, 12:45 PM
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Thanks Vince.
I'll see about the valve body if no codes seem to come up.
The car is still under factory warranty, so it won't cost me anything to get it serviced, but I want to diagnose this myself and go in and tell the dealer what the exact problem is, rather than go through round after round of guessing games.
I'll see about the valve body if no codes seem to come up.
The car is still under factory warranty, so it won't cost me anything to get it serviced, but I want to diagnose this myself and go in and tell the dealer what the exact problem is, rather than go through round after round of guessing games.
