geh3

it there a fix for the A8 transmission delayed/jerking issues from gear 1 to gear 2 after a cold start,

C-Vette 2017

Good question.

saleen556

geh3

SO when I first start my C7 ( now has 4500 miles on it) then start out, the upshift from 1st to 2nd is scary, much hesitation but it eventually get there, all other shifts are ok. After the engine heats up a bit, all works normally.. By now I would think that GM has a solution for this????

Kevin A Jones

It's been reported repeatedly via posts on the Range Device threads that the V8.6R1 has helped reduce considerably or eliminated the rough 1>2 shift issue for the A8.
Search the threads.

ExRedRacer

What year is your Vette?

There are any number of threads about this known problem. Generally, some Vettes built before 11/2015 are more prone to problems and those built after that date are less prone. GM made some big improvements at that time.

NSC5

At the first start of the day do a 1 to 2 to 1 shift via the paddles while stationary. This pre-fills one of the clutch pack actuators that is large and somewhat slow on the initial fill and avoids this issue. Not sure why GM hasn't updated software to do this sequence automatically at cold start since part of the fast shift strategy is a partial fill of next expected actuator(s).

My 2016 Z06 works flawlessly when this is done at the first start of the day.

The Kraken

Interesting. I am going to try this.

Wemattson

My 2017 with 3500 miles just started doing the 1-2 hard shift after a cold start. It was very surprising when it first happened. I'm going to try this as well. Thanks.

Flame Red

What Year?

I had this problem on my '15 and GM flashed a new tranny software and it was gone.

C-Vette 2017

Mine is a 2017 LT2 The white one in the photo.

Squeaky Wheel

Just make that first shift or two in the manual mode using the paddles. Then if desired you can go back to normal. Problem solved.

jimjimsC7

I haven't experienced this or any other problem with my 2019 GS A8. I do let it warm up a couple minutes before starting off.

PLRX

I did basic research when I ordered my 2016 in October 2015 and I already knew to stay clear of that A8.

CJ Willys

A8 in the GMC Sierra truck also jerks 1st to 2nd, mostly when cold. Mine & a buddy's does it.

joemessman

They actually have to replace the stator assembly in the transmission. The stationary part of the fluid part of torque converter. ... The torque converter assembly is a fluid coupling which transfers engine torque to the automatic automaticgear box.

Rebel Yell

knowing what year model, and how many miles you have will help with the answer.

My '16 with 8k miles has had a funky first change of the day since new. After that all is well. If that's what yours is doing I think we all will agree that's the nature of the beast. Some here will start there engine, let it run a minute, put the trans in "sport", and hit the upshift button to get that first change out of the way before they leave the garage. I have a long driveway, and the trans will shift to second before I get to the road way. There's probably nothing wrong with your trans, it just takes awhile to get used too.

NSC5

Joe,
The problem you describe is due to fluid drainback while the vehicle has been sitting for awhile and the symptom is the vehicle would not move or was slow to move at the initial startup. The revised stator shaft support assembly addresses that issue

The drainback issue was caught fairly early in production but the slow fill for the specific clutch pack actuator is a separate issue. With the harsh initial 1 to 2 shift there is no problem getting the vehicle moving in either forward or reverse after it has been sitting for some time but the initial 1 to 2 shift will be harsh.

I am surprised GM was caught flat footed with the slow fill issue because they had experience dealing with that when they first started using the Allision 1000 series in their heavy duty pickups 18 years ago. The Allision automatics are also clutch to clutch type automatics and due to their need to handle a very high level of torque under high vehicle load situations their clutch pack assemblies are large and the hydraulic actuators displace a lot of fluid. Some fine tuning was done early on to resolve some slow shift scenarios, particularly down to a lower range, to resolve customer complaints and they did a good job with it. My 2001 GMC 2500HD diesel was much improved after the update, the revised 6 speed version in my 2006 was even better and the current Allison 1000 in my 2018 is the best of the bunch. Due to their required heavy duty construction they will never shift as fast as the 8L90 but GM, in conjunction with Allision, has done a very nice job with that transmission and there is no good reason not to address the same sorts of issue that detract from the 8L90.

SRQStingray

Gm should include a Range device with every A8.

iclick

The delayed engagement should be fixable by referencing #16-NA-014 (attached), which like the AFM shuddering issues requires pulling the tranny. It's an old document and may have been updated.

The hard/sluggish shifts when cold may be fixable by resetting adaptive learning. This article may help.