Hmaringer

Does anyone else experience a hard shift from 2nd to 1st if you are in manual mode on the A8 z06? When I am using the paddles and lets say I'm in 2nd gear and and coming to a stop, when the computer shifts from 2nd to 1st by itself its pretty aggressive and the car definitely stutters for a second. Its not like this on any other gears and if I am in 3rd coming to a stop or any higher gear it doesn't do this when it automatically shifts down to 1st. Is this normal or should I bring it up at my service appointment next week?

Thanks!

pkincy

My 2nd to 1st shift was very hard when the car was new. Less than 1000 miles. Now with 5500 miles not so much. But yes there are times when I am coming to a stop especially if I go from 2nd to 1st when nearly at a stop that it is not terribly smooth. One way to avoid that is to do pull the left paddle twice rapidly and hold it on the second pull. The A8 will shift down as far as possible given the rpm when you do that, so if you are under 25-30 or so it will go straight to 1st from whatever gear you were in and I have found that shift to be very smooth plus you get a nice roar as the rpms come up to match your speed in first. Also if you are going to fast for 1st the tranny will only go down to 2nd.

And yes, I drive the A8 in manual about 95% of the time.

NSC5

I don't notice this with my 2016 Z06 but because the 2 to 1 down shift is infrequent (normally it skips 3 to 1 when slowing to a stop in full auto mode or in manual mode when allowed to down shift automatically from third or higher when slowing to a stop) it may not have learned that shift properly.

The only somewhat rough shift I have experienced with mine is the initial 1 to 2 shift after the first start of the day and I now avoid that by paddle shifting up to 2 and then back to 1 with the brake applied right after shifting into drive. I have a long driveway and by the time I reach the street where it is ready to shift into 2 the transmission has exited temporary paddle shift mode and the automatic 1 to 2 shift is smooth.

You can also immediately exit temporary paddle shift mode by holding in the up paddle for more than one second.

Frodo

I've seen posts about this and I've had a few hard down shifts in my '15 base coupe in manual mode. After much thinking I've come to a couple of thoughts that may bear consideration. Caution, I ramble.

First of all is the rev match that is always on in the A8 world. I love this feature, especially when heard through open NPP exhaust. But sometimes things don't appear to work out exactly as planned. Let's say you're slowing down for a stop using brakes and rev matched down shifts. The computers are hard at work calculating speed, rate of braking, engine rpm, gear ratio, expected future requirements, etc. Lots of stuff happening and the rev match rpm for the downshift is a moving target. So let's say for one reason or another the rpm needed for first gear at the current speed needs to be x rpm but by the time the rev match and shift occurs you've slowed even more than anticipated by the software and now the rpms are a bit too high. Or maybe the revs are high for some other reason. The car will surge or feel unduly harsh due to the over revving of the rev match software. The Z06 will likely feel that even more than a base due to the much greater torque available. Remember how remarkably strong and fast that Z06 is in first gear? It wouldn't take very much to make shifts seem hard with all that power at hand.

Also under consideration is the A8 and its computer and software. Adaptive, they say. This implies learning as well as anticipation. Remember above I mentioned anticipated future requirements? What if, simultaneously with the over rev matched rpm, the transmission software decides future requirements might include a power on roll out of a curve? The computer doesn't know, its trying to anticipate. The software requires a fast shift down to first, clutches engaging hard. Couple that with an over revved engine. That would sure get your attention. I remember reading one post where the driver said it felt like being hit from behind, it was so hard. What if the same sensory inputs caused both engine management and transmission management computers to shift into a more aggressive mode while you're calmly slowing for a stop? Unexpected results occur sometimes.

There's probably other scenarios where such results may occur. There may be mechanical faults known or unknown that can cause such performance. Above is just a scenario where I can see hard shifts being an unanticipated result of normally operating systems. If the transmission shifts smoothly in auto mode but sometimes shifts hard in manual mode then I wouldn't worry about it, as I don't worry about my own A8. In manual mode things may not always work out as planned due to the human variable and the software's anticipatory algorithms.

I've about quit shifting to first if I'm stopping, allowing the computer to make the final down shift. When I do downshift to first I'll wait until second gear's rpm drops to below 2000 so the rev matched rpms aren't too high to begin with.


That's just a thought, though. I'd love to hear it explained by someone who actually knows the design characteristics of the drive train.

rodney123456

when in manual mode on the a8 about what rpm do you shift at normal driving?

Frodo

In normal driving I usually downshift about 2000 to 2500 rpm unless I want a lot of that wonderful burble sound, then its a little higher. Much lower rpm than that just isn't much fun. I wait until below 2000 for a downshift to 1st just to keep things smoother, if I down shift at all. I've downshifted at much higher rpms on the Dragon and places like that. I don't track nor do I have experience with that. Downshifting 4th to 3rd or 3rd to 2nd at 4 grand or higher makes a huge noise.

Those who have more experience and training chime in.