Tiptronic Transmission problem Audi transmission problem / gremlin:

Before anything else, I just want to say thanks to everyone who reads this through and offers any experience, insight, input, opinion, etc, BUT, I don’t think that I have a problem with my transmission itself, or a problem with the transmission’s valve body or solenoids. This gremlin seems like an input / signal problem. I think that the transmission is getting an input from the car somewhere, which is causing the transmission to be confused. Like from a sensor which is on the way out, or needs to be recalibrated. Blaming the transmission and suggesting replacement seems dismissive and “safe” for if you don’t know what inputs that a transmission uses to make shifting decisions. A noteworthy percentage of transmissions are replaced just to find out that the problem is still there, so I would like to consider what is actually wrong before even considering replacing the transmission.

So the car is a 2008 Audi S4, with the six speed Tiptrontic, which I believe is the “6HP19A” transmission. The gremlin is that the car gears the transmission upwards too early, before the RPM’s can climb normally, and unless the throttle is very light, it gears up violently as it skips quickly through gears before the RPM’s can even climb. Unless you are very light on the throttle, you can hear the bang/knock as the car tries to skip through multiple gears. It climbs to 6th gear before reaching 60km/hr (40mph), even in Sport driving mode, when it should only be in 3rd gear. On highway in 6th gear, as you ease into the throttle to try and downshift, then the car misses as it tries to get down into 5th gear, and the rpm’s just flare as if it tried to downshift but you stay in 6th gear. If accelerating from a dead stop with medium throttle, then the car will violently jump prematurely into 3rd and 4th gear unless you are very light on the throttle. It jumps into higher gears too soon regardless of throttle, but it is not violent if you are very light on the throttle. Even accelerating from a stop with light throttle, you need to use the Tiptronic to keep gearing the car back down to avoid bogging down the engine.

While at cruising speed, and while driving light on the throttle, the transmission jumps upwards into gears to the point that any acceleration would be bogging down the engine since the car is in too high of a gear, and it won’t gear down as you increase the throttle. Unless you manually gear down (using Tiptronic) to accelerate while cruising, the transmission wants you to accelerate the car holding at 1200rpm (or where ever the rpm are in 6th gear). When using Tiptronic to manually downshift in order to accelerate, the car will put itself back into too high of a gear within a few seconds. When gearing down manually to accelerate, the car will sometimes fight as you try to accelerate and it will violently put itself back up two gears with a thump/bang.

At red lights, the car will sometimes “buck” noticeably, as if I had quickly released and stabbed the brakes. When this happens, if you look at the middle of the cluster (between RPM gauge and speedometer) then you can see the car jumping between first gear and fifth gear, or first gear and second gear. The transmission is getting an input from somewhere telling it to shift gears when it shouldn’t be shifting. I think the red light behaviour is a good example of why the transmission is getting a bad input somewhere.

Sometimes when trying to get the car moving I can’t get the torque converter to lock up in first gear, so then my option is to either (a) restart the car, or (b) ease into the throttle until the car decides to skip itself prematurely into second gear from a dead stop.