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Gorehamj

GM 8-Speed Transmission Lawsuit Heats Up - Does Yours Shudder?

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Posted (edited)

So if there is an adaptive transmission, why did my 2019 Silverado drive perfect from day one? Why can I drive my father's f150 with no issues? My wife's 2018 cruise with no issues? It doesn't even make sense, so if you drive mostly conservative the transmission won't let you pass a car? Or if you drive all highway the second you go into town the transmission doesn't know what to do?

 

When they say adaptive, they just mean it adjusts to the current way your driving, meaning if you're in town it will shift more and if you're in the country on a highway it will shift less. Basically similar to Tow/Haul mode. I had my 2016 for 10k miles, it drove just as bad the entire time, and I was the only person to ever drive it.

 

https://practicalmotoring.com.au/voices/does-an-adaptive-gearbox-really-learn-how-you-drive/

Edited by worldaccordingtojim

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Because I no longer own a GM vehicle, I'll be leaving the forum. But as a last response, Yes, the GM profile system, the GM programming algorithm and the rather large memory capability of the control unit means that driver habits are recorded and used in slightly altering vehicle operation. Unfortunately, because the current trend is "fuel economy", this usually means that "adaptive" translates to sluggish.

 

In my current vehicle, an F-150 5.0 10 speed, it drove great to begin with, but after the first 1000 miles or so it became sluggish when accelerating from lights, did more gear skipping (non-sequential up-shifting), and generally required mode changes (Eco, Normal, Sport, etc) to get some of the performance back.

 

And the characteristics of "adaptive" seem to permanently remain as long as the control unit has power. Simply turning off the engine does nothing to change any of the stored data. However, we have learned that we CAN force the control unit to begin "re-learn" by removing and re-inserting the power fuse for the controller (in our vehicle it's fuse 109 I think, but check your own vehicle system). This basically gets rid of the sluggish operation in "Normal" mode until re-learning is once again completed.

 

But then again, I have no problem driving conservatively and saving fuel so I think I let it learn and leave it that way. If more performance is desired, I'll simply switch modes.

 

I wish you all the luck in the world with your GM vehicle.

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Took my 2015 6.2/8 spd Silverado in for an oil change a couple weeks ago.  While talking to Customer Service Rep I mentioned that my tranny was still shifting hard between 1st to 2nd and vise-versa at low speeds.  And, the three quick-flash reprogram hadn’t fixed anything.  Also stated if they couldn’t come up with a fix I was going to demand a new tranny.  Rep, said that a new tranny might not correct the problem as they have made some swaps and customers still had the problem with the new tranny.  Then, he stated that there was a new ATF out that was giving excellent results.  Said it was Mobil 1 Blue Label.  I said let’s give it a try.  So, long story short, they did the flush per the SB and put in new Blue Label fluid.  Almost immediately I could tell a difference.  And, now that I’ve put about 100 miles on it the shifts are smooth.  Haven’t had a single  hard shift since.  Fingers crossed 🤞! 

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8 hours ago, Snoringbear said:

Took my 2015 6.2/8 spd Silverado in for an oil change a couple weeks ago.  While talking to Customer Service Rep I mentioned that my tranny was still shifting hard between 1st to 2nd and vise-versa at low speeds.  And, the three quick-flash reprogram hadn’t fixed anything.  Also stated if they couldn’t come up with a fix I was going to demand a new tranny.  Rep, said that a new tranny might not correct the problem as they have made some swaps and customers still had the problem with the new tranny.  Then, he stated that there was a new ATF out that was giving excellent results.  Said it was Mobil 1 Blue Label.  I said let’s give it a try.  So, long story short, they did the flush per the SB and put in new Blue Label fluid.  Almost immediately I could tell a difference.  And, now that I’ve put about 100 miles on it the shifts are smooth.  Haven’t had a single  hard shift since.  Fingers crossed 🤞! 

Sweet, following along to see how this turns out.  

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Has anyone successfully had this issue fixed?  I've had my '16 Sierra 1500 Denali in to 3 different GM dealers, tranny fluid changed 3 different times, still drives like shit.  Same symptoms as everyone else.  Shuttering when coming to a stop, searching for gears in "stop-and-go" traffic, random clunks and hard shifts sporadically, and this metal "ping" sound after moving again from a stop.  Also, I have a bad squeak between 1st and 2nd when you are rolling and accelerate.  Think of rolling to a stop, stopping, and then pulling out.  Most noticeable when transitioning to an include.  I can reproduce it all the time and dealers telling me it's just an actuator. Maybe.  Or maybe the clutch packs are shot at 40k miles??  So frustrated...

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Yes.  Read my post a couple up.

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I absolutely hate my 6 speed! I wanna sell it it drives me nuts! Has anyone ever filed lemon law on these trucks? 

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On 6/10/2019 at 6:36 PM, Snoringbear said:

Yes.  Read my post a couple up.

Problem I'm having is the dealer drove it around hooked up to their PC and scope and the PC says there is no shutter.  Can feel it every time. So dealer says since the PC says no shutter, nothing to fix.

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There are two distinct and separate tranny problems.  One is hard shifts, primarily in the lower gears. In my case, it was primarily between 1st to 2nd and 2nd to 1st usually when slowing way down for a yield or right turn or a California stop.  The other frequent problem is torque converter shudder, in my case it was the most obvious while driving at mid-speed, say 40 ~ 50 mph.   I think the torque converter problem is the most difficult to diagnose because the Silverado rear suspension (leaf springs directly mounted to frame) is pretty much the same as was on my grandfathers 1952 Chevy and on concrete roads with tar strips and antiskid groves and such it’s difficult to tell what’s what. .  Anyway, GM is long overdue for an upgrade of their 1500 rear suspension. system.  

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As I mentioned upstream, the new and improved ATF has eliminated both problems in my truck.  Here’s some info about this magic elixir.  Btw,  there’s a SB out in the ATF and change out procedure.

https://gm-techlink.com/?p=11127

 

 

 

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On 6/14/2019 at 4:41 PM, Snoringbear said:

As I mentioned upstream, the new and improved ATF has eliminated both problems in my truck.  Here’s some info about this magic elixir.  Btw,  there’s a SB out in the ATF and change out procedure.

https://gm-techlink.com/?p=11127

 

 

 

Has this still been working on your truck? I just put mine in the shop and they claim its been working well. 

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I'm in the class action suite. Signed my retainer last week. We'll see what happens in a couple years...They said it could take 1 to 2 years

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15 hours ago, mnm99 said:

I'm in the class action suite. Signed my retainer last week. We'll see what happens in a couple years...They said it could take 1 to 2 years

What is the expectation?  What will those in the suite demand?  Money, buy-back, tranny replacement?

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I have no idea. What I was told from them when they win cases like this is either, repair the tranny, Replace the tranny or buy back the truck. I'ts going to cost me some time in court with them, but I don't care really. Hoping something will be done.

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