V4 mode problem ?
Team Owner
Joined: Sep 2010
Posts: 32,042
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Your transmission may be on its way out. V4 is killing the transmissions. Start camping out at your Chev. dealer until they replace or fix your transmission. It's not supposed to be this way.
Team Owner
Joined: Sep 2010
Posts: 32,042
Likes: 4,610
Le Mans Master
Joined: Apr 2001
Posts: 8,133
Likes: 144
From: Ex-SF Bay Area; now happily Denver area
I have a 2016 Z51 A8 with 7200 miles and going between V4 and V8 was always seamless and totally unnoticeable However, due to the threads on this forum I decided to get the Range AFM. Now I never go into V4 mode and the car seems to shift better. Mine always shifted pretty well before but seems a little better now. Not sure why, and it's not a big difference, but does seem smoother.
E-Ray, 3LZ, ZER, LIFT
Joined: Sep 2007
Posts: 34,937
Likes: 12,351
From: NE South Carolina
As others have said those of us with standard shift C7s don't have to deal with the switch to V4 unless we drive in ECO. That defeat device will allow you the same. Latest info indicates they have fixed the early issues.
PS: Just put "C7 V4 disabler in Amazon." Easy plug-in install and $140 will make your $60,000+ perfect! Available from many vendors.
Last edited by JerryU; Nov 3, 2018 at 06:49 AM.
Melting Slicks
Joined: Aug 2014
Posts: 2,746
Likes: 916
Let's be clear here. It's not killing the transmission. It's killing a component of the transmission called the torque converter.
Melting Slicks
Joined: Aug 2018
Posts: 2,781
Likes: 3,105
I have an M7 and for long trips on the highway I will use Eco mode and the V8-V4 transition is seamless. I have no issue using Eco and have no idea why so many are against it. Ya I know you don't buy a car like this to drive it in Eco but that doesn't mean there aren't times when it is beneficial.
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Le Mans Master
Joined: Jan 2006
Posts: 6,800
Likes: 2,653
From: Down south in Dixie
I have an M7 and for long trips on the highway I will use Eco mode and the V8-V4 transition is seamless. I have no issue using Eco and have no idea why so many are against it. Ya I know you don't buy a car like this to drive it in Eco but that doesn't mean there aren't times when it is beneficial.
Le Mans Master
Joined: Jan 2006
Posts: 6,800
Likes: 2,653
From: Down south in Dixie
They certainly have, and it's all across the GM models running the A8. It seems that GM trough the years always manages to come up just short of good in many of it's designs. As with many big manufacturers GM must listen to the bean counters more than they do the design engineers.
Tech Contributor
Joined: Oct 1999
Posts: 41,037
Likes: 9,801
From: Charlotte, NC (formerly Endicott, NY)
I have an M7 Z06 that I run in Eco mode most of the time when I am not on the track. The only way I know the engine switches from V8 to V4 mode is the exhaust which is set in permanent Track mode gets quieter when the engine is in V4 mode and gets loud when it is in V8 mode. When it switches back to V8 mode I can feel more acceleration but that is why it switched back to V8 mode so it could accelerate better. DOD had some valve lifter issues on the trucks that incorporated that design about 10 years ago but that seems to have gone by the wayside and is pretty much trouble free on the new vehicles.
Bill
Bill
Team Owner
Joined: Sep 2010
Posts: 32,042
Likes: 4,610
Team Owner
Joined: Sep 2010
Posts: 32,042
Likes: 4,610
They certainly have, and it's all across the GM models running the A8. It seems that GM trough the years always manages to come up just short of good in many of it's designs. As with many big manufacturers GM must listen to the bean counters more than they do the design engineers.
Last edited by Skid Row Joe; Nov 4, 2018 at 04:19 PM.
Melting Slicks
Joined: Aug 2014
Posts: 2,746
Likes: 916
Go back and re-read what I posted. I said it is a component of the transmission. My point is that the cost to buy a new torque converter is a lot less than having to buy a whole new transmission. In other words a killed torque converter is cheaper to fix than a killed transmission. Folks need to know what they are signing up for.
Last edited by lakemg; Nov 4, 2018 at 04:22 PM.
Intermediate
Joined: Jul 2012
Posts: 48
Likes: 4
From: Spring Texas
V4 Mode
My 2017 Stingray had no issues at all with this and got 30+ MPG on open long trips. Now my 2019 Grand Sport with less then 3000 miles is a completely different story!!! Very distinctive shake on/off 15-30 seconds, you can see it in the Tack like if it was misfiring and gets 22-24 MPG on first open long trip. My wife even looked at me and asked if the road was that rough or was it the car. Became clear after a while it was the car and only did it in V4 Mode. Dropped off and dealer Saturday, now to see what they say.
Pro
Joined: Jan 2014
Posts: 566
Likes: 163
From: Earleton Fl
I had a 2015 Z51, and my TC problems started out just like what you are describing! Watch you tach when you are driving, and you will see a small fluctuation in the RPM maybe 50 or so RPM's. They replaced the TC on mine-twice. I would get it in, and have it checked. I understand that the current cure for this is a new type of fluid! GOOD LUCK!
Racer
Joined: Nov 2015
Posts: 260
Likes: 87
From: Brighton MI
New fluid which was released early in 2019 is Mobil 1 Syn LV ATF HP 124715. This was installed in our 2016 about 2 months ago with significant improvement in shift quality including the initial first to second shift when cold. Subsequent to fluid change I installed Range AFM Disabler which eliminates V4 mode. Happy with this so far. I've also got a couple of 10 oz bottles of Lubegard Platinum on the shelf which should create an improvement. By design the Torque Converter is supposed to slip 10 RPM when in V4 mode. 10 RPM slippage has to be very difficult to control. As someone else mentioned, there are many threads on this issue. Good luck.
Tech Contributor
Joined: Oct 1999
Posts: 41,037
Likes: 9,801
From: Charlotte, NC (formerly Endicott, NY)