Shifting issues
07-20-2018, 07:56 AM
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Shifting issues
Hello everyone, I just joined this forum page hoping somebody may be able to help me out. My daughter has an 08, A4, 2.0 turbo. She has been experiencing some intermittent strange shifting experience. It's automatic, by the way. During normal acceleration, when the tachometer reaches 3000-3500 rpm, when it would normally upshift, sometimes it will hesitate and stay at the high rpm for a second or two, before shifting into the next gear. Then it will shift normally, no clunking or anything unusual. And during that second or two, the gas pedal is unresponsive. Has anyone experienced anything like this before? I tried to get it on video, but failed so far.
07-20-2018, 08:39 PM
#2
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If it's a US model year 2008 A4, then it would be a "B7" generation product. B8 in the US is 2009-2016.
That said, I have mine do the same thing from time to time. Typically 2 to 3 gear shift. It's rare; if I think back, I think it's only been when starting out, near the neighborhood.
Even if I modulate the pedal to drop the rpms and get back on it, it stays in the low gear. I have to back out of the pedal entirely for a second or two and let it wind down below that 3k'ish point, then I can get back on the gas and it'll upshift.
Since I've never done the trans fluid drain/fill (appears a flush is not recommended by ZF, the transmission maker), I've not really tried to diagnose it. Wonder if something is sticking in the mechatronic or whatever manages the stall speed (I think that relates to when shifting is allowed).
So I'm not sure if the computer is messing up, failing to signal the shift, or if the transmission is messing up and failing to shift.
I get a similar problem from time to time with the engine from a stop, where I'll press the accelerator pedal to go, but the car just drifts out at low rpm for 2 seconds before actually rev'ing up and going.
So am curious how that plays out for you if you find some resolution.
That said, I have mine do the same thing from time to time. Typically 2 to 3 gear shift. It's rare; if I think back, I think it's only been when starting out, near the neighborhood.
Even if I modulate the pedal to drop the rpms and get back on it, it stays in the low gear. I have to back out of the pedal entirely for a second or two and let it wind down below that 3k'ish point, then I can get back on the gas and it'll upshift.
Since I've never done the trans fluid drain/fill (appears a flush is not recommended by ZF, the transmission maker), I've not really tried to diagnose it. Wonder if something is sticking in the mechatronic or whatever manages the stall speed (I think that relates to when shifting is allowed).
So I'm not sure if the computer is messing up, failing to signal the shift, or if the transmission is messing up and failing to shift.
I get a similar problem from time to time with the engine from a stop, where I'll press the accelerator pedal to go, but the car just drifts out at low rpm for 2 seconds before actually rev'ing up and going.
So am curious how that plays out for you if you find some resolution.
07-21-2018, 01:07 AM
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Thanks so much for the reply. You're right, it is a b7, and I really only learned the difference after I made the post. You're describing almost exactly the same problem. It's headed to the shop next week. I'll post the results
08-03-2018, 01:45 PM
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So the trans fluid flush did work. Then a few days later, the problem seemed to be back, worse than ever. My shop found a short in the brake light switch, which was somehow causing the transmission to jump into neutral. Replace brake light switch, problem gone.
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