Apocolips

I’m not sure if this is normal or not so I’d like to see if anyone else has this issue. I have a 2017 GS with an A8. The transmission is smooth and shifts great. However, when slowing to a stop it will jump from 3rd to 1st without going through 2nd. This causes an abnormal hard down shift. This only happens when stopping. Is this normal or is there a problem with the transmission programming? Thanks!

Rebel Yell

My previous '16 went from 3rd to 1st with no jumping, and my now '19 is the same. It's my understanding that these tranny's are designed to go from 3rd to 1st so it would be a smoother transition, but I can't say if that's a true fact or not. The A10 in my wife's Mustang GT goes from 3rd to 1st also without any jumping. Even my F-150 with an A6 is the same. You may want to have your's checked. Good luck.

NSC5

Going from 3 to 1 is normal behavior, the only time you would need the 3 2 1 sequence when slowing is if you were manually shifting to use engine braking. But it shouldn't be a hard shift. Get it looked at and it may need to be put back into learn mode by the tech to relearn this shift. These are clutch to clutch architecture transmissions without the slipping bands and overrunning clutches of older automatics and shifts are achieving by precise timing of the release of one or more clutch packs at the same time others are being applied. If the timing is off then rough shifts and shift flaring will result. The controller adjusts apply/release timing and pressure based upon actual shift behavior but if it gets too far off from desirable the correction is so slow (requires a huge number of shift events for that particular shift sequence) that it needs to be forced back into a fast learn mode where the problematic shift is then repeated multiple times.

Gearhead Jim

2017 Z51 A8

Ours also goes from 3 to 1 as we come to a stop. If we come to a complete stop, that works fine. But if we slow to about 3 mph instead of a complete stop, and then get on the gas lightly, the tranny somewhat lurches into 1 because adding some throttle "forced" the shift.
That programming might work fine in an EPA test cycle, but it's kind of a PITA for normal driving.

kensredvette2

^^Yeppers, happens for me. However, noticeably improved after an ATF fluid change, but not gone. From my experience, range device has no effect on this particular issue.

FunDriver

2016 A8 Z51 and no problems.

f1reb1rd

i have a 2017 z06 and it also does that but i have learned that if i slow down at a slower speed when coming to a stop it does not do that

NSC5

Good point Jim and that does confuse the transmission especially if your timing is the "perfect storm of wrong". When it is getting ready to make the coasting shift from 3 to 1 and you roll back into the throttle it may initially try to stay in third but with enough throttle tip in it will make a shift to second or first depending upon vehicle speed and throttle amount. So in a short amount of time the transmission has revised its plans two or three times leading to less than stellar behavior as the clutch pack fill/empty keeps shifting between clutch packs based upon rapidly changing commands from the controller.

The completely different but still electronic with clutch to clutch architecture heavy duty Allison auto in my GMC pickup also makes some rough shifts if you transition from off throttle low speed coast down back to throttle when the timing is just wrong.

Or as a friend who is a retired LEO put it to me, you aren't supposed to be making "rolling" stops anyway

capeli