Any common knowledge on the ZF 8 speed in the 2016 Yukon?

[meep]

A good friend of mine just picked up a 2016 Yukon xl with the 8 speed. After driving it a couple days and getting it good and warmed up, the transmission notably shudders in most shifts. 130k miles on it. Google tells me this is a known problem and a class action lawsuit hit at some point.

I suggested 1-2 drain fills and possible dose of lubeguard. He’s going to start with 1 d/f and see where that goes.

is there known remedy at this point for this unit?

 

[b_b]

they were shipped with the wrong fluid. im not sure what the correct fluid is and if it will even fix it by this point.
its also not a zf unit. its an internal gm design.

 

[Nuclear_42]

There's been several issues with GM 8-10 speed transmission from their trucks and suv. My understanding is the transmission operate at a very high temp. The cooling thermostat isn't the best. Over time the ATF fluids starts breaking down and unable to hold film. Now if it just started shuddering your good to just change the fluid. Now people that drive it shuddering for 2-3 years eventually cook the converter. I recommend Amsoil Signtuare ATF. Others may recommend Red Line. I personally experienced this issue and went through 3 torque converts and fluid changes. Amsoil went in and never looked back. AC Delco and Mobil band aid fix service bulletin fluid will not hold up in these transmissions period. You can do all the research you want. Everyone that uses ac delco or mobil eventually get the shudder back after. I haven't heard of anyone come back with shudder using the signature ATF which is made to prevent shuddering.

https://amsoilcontent.com/ams/lit/databulletins/g3110.pdf

 

[jhs914]

they were shipped with the wrong fluid. im not sure what the correct fluid is and if it will even fix it by this point.
its also not a zf unit. its an internal gm design.

This was the fix that GM came up with. Changing from a Dex VI to this solved the shudder in my 2017 8 speed: https://www.mobil.com/en/lubricants...products/products/mobil-1-synthetic-lv-atf-hp

However, if it was driven for 130K miles with Dex VI the damage to the torque converter will already be done from all of the torque converter shudder.

 

[joekingcorvette]

They have had excellent results on the 2015-2019 Corvette A8 automatics with what is called a "triple flush." They use a fluid different than the factory fill and have had great results. Yes, the class action lawsuit is well known and lots of info on this if you google it.

 

[ctechbob]

They have had excellent results on the 2015-2019 Corvette A8 automatics with what is called a "triple flush." They use a fluid different than the factory fill and have had great results. Yes, the class action lawsuit is well known and lots of info on this if you google it.

The thing with the A8 in the Vette is that it is programmed differently than almost everything else across the range. They programmed out the lockup in lower gears so the wear on the converter isn't as bad, and therefore neither is the shudder problem.

Everything else didn't receive any update other than the fluid, which is a patch at best. The records that have been released are a fascinating read.

I would say he's probably on borrowed time. @clinebarger can probably speak better to it, but a preventative rebuild might not be a bad idea. Either replace the converter and update the valve body now, or wait for it to frag completely and rebuild way more.

https://www.cohenmilstein.com/sites/default/files/Index%20of%20Misc.%20Exhibits%20Document%20-%20GM%20Litigation_0.pdf

A few choice excerpts:

(The 'Option B' they speak of is the new, updated fluid)

The plaintiffs’ expert, Alice Wachs, reviewed warranty service data produced by GM through discovery and predicted that warranty claim rates among 8L-equipped class models eventually would range from 61% to 100% for various models within the expected vehicle lifetime of 10 years or 120,000 miles. Wachs also reported that a similar review conducted internally by GM predicted future warranty claim rates matching her figures.

McVea cited internal GM documents from the defendant’s study of the transmission problem that showed that GM selected an ATF designated as “212B” and a friction material known as “LuK WFP6300.” Other documents showed that GM’s engineers found this combination to be problematic because the 212B fluid was unusually sensitive to moisture, and because the WFP6300 material had poor friction characteristics....... McVea cited GM presentations highlighting the inappropriate combination, noting that the fluid selected originally was intended to be used with a “carbon fiber” friction material, but the fluid was not changed when GM decided, in 2012, to switch to the “paper based” WFP6300 material, ostensibly citing a $2 per unit savings due to a discount from the supplier that had proposed to produce both the clutch material and torque converter assemblies. Ibid. The problematic combination was referred to contemporaneously by GM engineer Randy Melanson as “the worst friction system we got, and it’s only going to get worse with mileage, no matter what we do.”

 

[Elroy the Brave]

A good friend of mine just picked up a 2016 Yukon xl with the 8 speed. After driving it a couple days and getting it good and warmed up, the transmission notably shudders in most shifts. 130k miles on it. Google tells me this is a known problem and a class action lawsuit hit at some point.

I suggested 1-2 drain fills and possible dose of lubeguard. He’s going to start with 1 d/f and see where that goes.

is there known remedy at this point for this unit?

 

[clinebarger]

Sure it has a 8L90E?

 

[LDM]

A good friend of mine just picked up a 2016 Yukon xl with the 8 speed. After driving it a couple days and getting it good and warmed up, the transmission notably shudders in most shifts. 130k miles on it. Google tells me this is a known problem and a class action lawsuit hit at some point.

I suggested 1-2 drain fills and possible dose of lubeguard. He’s going to start with 1 d/f and see where that goes.

is there known remedy at this point for this unit?

8L90E, not the ZF8. If he is getting the shudder, have him take it in to a dealer and have them perform 18-NA-355 TSB. The original fluid in these absorbed water and they switched to a different blue label Mobil 1 LV ATF that is suppose to fix it. Had it done on my 2018 Sierra for the hard 1-2 shift and I haven't had the problem since.

Some people still do have the issue after the fluid exchange, the only thing I've seen help at that point is a whole torque converter replacement or reprogramming the transmission to eliminate some of the slip that is present in most of the factory calibrations.

I have heard of the Lubegard Shudder Solution but I don't know anyone that has tried it.

 

[meep]

Thank you all. ive shared the info in this thread with him and he’s taken it to a mechanic he trusts with some points from this thread. @clinebarger - his mechanic asked the same thing - my friend seemed confident saying it was an 8-speed and from the passenger seat the count seemed right, but he’s not as close to the underside of a vehicle as he used to be, and TC lockup strategies can confuse armchair shift counting.

I suspect that there’s still good life left in the unit and told him if his mechanic can’t get it right, that I’ll take a stab at an amsoil d/f 2-3x before he considers bigger expenses.

again, thank you for the details in this thread. Super helpful.

 

[LDM]

Thank you all. ive shared the info in this thread with him and he’s taken it to a mechanic he trusts with some points from this thread. @clinebarger - his mechanic asked the same thing - my friend seemed confident saying it was an 8-speed and from the passenger seat the count seemed right, but he’s not as close to the underside of a vehicle as he used to be, and TC lockup strategies can confuse armchair shift counting.

I suspect that there’s still good life left in the unit and told him if his mechanic can’t get it right, that I’ll take a stab at an amsoil d/f 2-3x before he considers bigger expenses.

again, thank you for the details in this thread. Super helpful.

The 8 speed was offered on both the 5.3 and 6.2 in 2016, so its possible he could have either the 6 speed or the 8 speed depending on the engine option. All 6.2 engines only received the 8 speed, the 5.3 it was available on the higher trims but most came with the 6 speed.

If he wants to verify, he can put it in manual mode and go through the gears. If it has the 7 and 8 then he definitely has the 8 speed.

 

[Slick3914]

It’s not a ZF8

 

[2kredss]

You don't know what you are talking about. The 10 speed in my sierra runs at 147 all day long. It doesn't know what 200 degrees is pulling a 32 ft. Tt. Get your facts right before blowing off with the mouth.

 

[nicholas]

A good friend of mine just picked up a 2016 Yukon xl with the 8 speed. After driving it a couple days and getting it good and warmed up, the transmission notably shudders in most shifts. 130k miles on it. Google tells me this is a known problem and a class action lawsuit hit at some point.

I suggested 1-2 drain fills and possible dose of lubeguard. He’s going to start with 1 d/f and see where that goes.

is there known remedy at this point for this unit?

LUBEGARD® GM 6 & 8-Speed Shudder Solution - Transmission Digest

General Motors has published multiple technical service bulletins pertaining to torque converter clutch shudder issues in their 8-speed transmissions. This problem currently affects 11 different models across 3 different OEM brands for the model years between 2015 and 2019. After implementing...

www.transmissiondigest.com

Try this..........

 

[Nuclear_42]

You don't know what you are talking about. The 10 speed in my sierra runs at 147 all day long. It doesn't know what 200 degrees is pulling a 32 ft. Tt. Get your facts right before blowing off with the mouth.

Wow what a way to be rude! Just because your truck runs good doesn't mean that's the fact on all GM 8-10 speed transmission. AC Delco oil breaks down and glazes the internals it's a know issue. Hence to the TSB for a Mobil one ATF fix. The 8 speed is also known to have a badly spec'd thermostat for the transmission. Again having a good quality ATF that resists breakdown over time solves these issues.

 

[ctechbob]

You don't know what you are talking about. The 10 speed in my sierra runs at 147 all day long. It doesn't know what 200 degrees is pulling a 32 ft. Tt. Get your facts right before blowing off with the mouth.

The 8-speed and 10-speed are completely different animals.

The 10-speed, both Ford and GM are designed around ULV fluid with much higher operating temps.

I would seriously question the 147-degree data. I've never heard of a 10-speed operating at that low of a temperature and by most accounts, they operate better above 160 degrees with them normally operating in the 190-210 range.

Also, I assume you're talking about using Amsoil in the 8L transmission, not a 10L. Amsoil doesn't make a suitable ULV product at the moment. Or at least they didn't a few months back.

 

[wwillson]

You don't know what you are talking about. The 10 speed in my sierra runs at 147 all day long. It doesn't know what 200 degrees is pulling a 32 ft. Tt. Get your facts right before blowing off with the mouth.

@2kredss I don't know how long you've been coming to BITOG, but we don't talk to each other like this.

 

[ctechbob]

Wow what a way to be rude! Just because your truck runs good doesn't mean that's the fact on all GM 8-10 speed transmission. AC Delco oil breaks down and glazes the internals it's a know issue. Hence to the TSB for a Mobil one ATF fix. The 8 speed is also known to have a badly spec'd thermostat for the transmission. Again having a good quality ATF that resists breakdown over time solves these issues.

It was actually water contamination that caused the shudder issue. Mobil made the original fluid to GM's specifications.

The problem was that the fluid was validated on a different clutch material and then late in the game GM switched from a carbon-based material to a paper-based one that was inferior in almost every way and then they didn't update the fluid.

The problematic combination was referred to contemporaneously by GM engineer Randy Melanson as “the worst friction system we got, and it’s only going to get worse with mileage, no matter what we do.”

GM Actually had meetings to determine if they were going to try and get Mobil to come off with some cash to cover warranty issues they were having with it. It was decided against, probably to keep from burning that bridge, but also because 'they made what we told them to'

If you have the time, I highly recommend reading through the class action documents that have been unsealed, it is a fascinating look into the workings of a huge company that f-ed up and then instead of pulling back and doing some emergency redesigns, turned the knob to 'FULL SEND' and held it there. Personally, I'm baffled why they didn't push the 10L into production to take the place of the 8L's when they discovered that the 8L was pretty highly flawed. They would still have had the problem to deal with, but they could have stopped the bleeding.

I'm also baffled why they didn't switch back to the carbon-based torque converter clutch, although maybe that was a minor concern they thought they cured with the fluid and decided to leave that be and focus on the valve body issues.