8 Speed Transmission

SilveradoRST · September 28, 2020

I know it is not Silverado T1 specific, but it looks like the 8 speed is sticking around. Does this mean GM is not going to stick the 10 speed across their entire line up like Ford?

https://www.gm-trucks.com/gm-throws-its-support-behind-the-silverado-sierra-corvette-camaro-transmission-and-engine-factories/

2016 Sierra Owner · September 29, 2020

14 hours ago, SilveradoRST said:

I know it is not Silverado T1 specific, but it looks like the 8 speed is sticking around. Does this mean GM is not going to stick the 10 speed across their entire line up like Ford?

https://www.gm-trucks.com/gm-throws-its-support-behind-the-silverado-sierra-corvette-camaro-transmission-and-engine-factories/

I think with the pandemic crap going on. GM was having trouble getting the 10 speed out to the factories. They opted for the 8 to keep going for now. We'll see I guess.

econometrics · September 29, 2020

It's really not a bad transmission in the new 2019+ models, save the harsh shifts from 1-2 that can happen pretty frequently. If they can get the 1-2 shift smoothed out, it's equally as good as the 10 speed, IMO. It rolls through the 2-8 very nicely.

The 1-2 on the 10 speed also can be harsh at times, according to some people.

Moend · September 30, 2020

I have an 8 speed on my 5.3 4WD and happy to report no issues after 14 months and 25k miles

SilveradoRST · September 30, 2020

45 minutes ago, Moend said:

I have an 8 speed on my 5.3 4WD and happy to report no issues after 14 months and 25k miles

What was your build date? Do you know if you have the new Mobil ATF?

O Town Denali · September 30, 2020

1 hour ago, SilveradoRST said:

What was your build date? Do you know if you have the new Mobil ATF?

My truck is in the shop as we speak. Built 9/18. 5.3/8 speed. 23 months 35K miles. Started shuddering about the last 500 miles.

Hope the fluid change does the trick.

My 2016 6.2/8 speed started shuttering at 40K.

econometrics · September 30, 2020

2 hours ago, O Town Denali said:

My truck is in the shop as we speak. Built 9/18. 5.3/8 speed. 23 months 35K miles. Started shuddering about the last 500 miles.

Hope the fluid change does the trick.

My 2016 6.2/8 speed started shuttering at 40K.

I'm trading my RST A8 in for a new one with an A10 if this ever happens to me. Too many horror stories from previous gen A8s.

Moend · October 1, 2020

7 hours ago, SilveradoRST said:

What was your build date? Do you know if you have the new Mobil ATF?

It was sometimes in Feb. Of 2019

Moend · October 1, 2020

Just now, Moend said:

It was sometimes in Feb. Of 2019

And it was built in Mexico

SilveradoRST · October 1, 2020

8 minutes ago, Moend said:

It was sometimes in Feb. Of 2019

Mine too, Feb 2019 but at Fort Wayne. So far I only experience some hard 1-2 if I don't warm it up for a few minutes before I go. Otherwise it is smooth 3-8. I'm always conflicted if I should bring it in anyway to get the new Mobile ATF or wait until I get the shudder. Heard some stories here and there about not flushing your trans or that the flush machine is contaminated with multiple ATFs. Not an immediate issue for me, Actually, not an issue at all for me right now.

Moend · October 1, 2020

5 minutes ago, SilveradoRST said:

Mine too, Feb 2019 but at Fort Wayne. So far I only experience some hard 1-2 if I don't warm it up for a few minutes before I go. Otherwise it is smooth 3-8. I'm always conflicted if I should bring it in anyway to get the new Mobile ATF or wait until I get the shudder. Heard some stories here and there about not flushing your trans or that the flush machine is contaminated with multiple ATFs. Not an immediate issue for me, Actually, not an issue at all for me right now.

I don't have to much trust or faith in the dealers arround me. They just don't care. That is why I do my oil changes myself (it is my Sunday relaxing routine).

Also, I was planning on changing my ATF after 2 years or 50k miles whichever comes first. It does not cost much 100~150 tops and a cheap insurance

O Town Denali · October 1, 2020

Back from the shop:

Early results show no shuddering and back to smooth shifts. I think I will just have the tranny flushed every 30K miles or so. These transmissions seem very finicky with the fluid.

I do like the tranny in the 2019 though. It shifts so much smoother than my 2016.

Edited October 1, 2020 by O Town Denali

Kristy F · October 2, 2020

Sorry for the long rant -- We have a '20 Silverado 1500LT (8-spd). Bought it w/16,000 miles on it on Aug 1. Hubby test drove it and I just did the financial stuff. A few days after we bought it, I drove it up to the store and noticed the awful shuddering starting @40mph and especially highway speed. Also, going over any kind of bump or groove in the road, it shakes horribly side-to-side. We had the tires rotated/balanced and an alignment. Didn't help. Took it to 2 dealerships and the first said they noticed a light shudder but no codes came up. Mentioned TSB 16-NA-019 but they didn't have a trans mechanic to work on it and referred us to the other dealership. Just picked it up today from the 2nd dealership. He said they test drove it and there's nothing loose in the suspension and he felt a light shudder but nothing abnormal.

I asked him that when it's time for us to take it in for the regular trans service, if they swap it out with the Mobil 1 - he said that's what is in the truck already (it came with it from the factory). He said they started putting it into the 2019 Trucks from the factory. I call BS but whatever. I looked in the manual and it says it takes Dexron-Hp so I'd assume that's what was put in it in the factory.

I hadn't heard about the 'Chevy shake" until I googled the shuddering. I noticed the comments about the trans fluid, torque convertor, driveshaft, etc. Very disappointed - we were excited about buying our first Chevy truck. That Tundra is looking pretty good right about now.

I guess my question is to take it to a third Chevy dealer and try again and maybe go on the test drive with the mechanic - and demand that they swap the fluid. I'm so pissed off right now but mostly just disappointed.

Kristy F

Jay P · October 2, 2020

The dealer is correct, it came with the updated ATF from the factory. The original fluid was hydroscopic (absorbs water) and the water is what caused all the problems. The newer Mobil 1 fluid doesn't have this issue.

GM is not the only manufacturer to have this issue, Audi had this in the past.

Since you got a used truck with 16k miles on it you don't know how it was driven prior to you taking it home. I would ask the dealer to reset the trans so it forgets all the learning it did prior to you owning the truck. It may cure the issues you are having. If they won't due that or it doesn't change the issue, take the tech or service writer for a ride to show them what your issues are. Much harder to say "no problem found" if you get them to see/feel the issue.

Jay