GM's 6th Gen V8 ! What would you like to see?

[silveradosid]

2020 2.7 with the 8 speed has 95k miles and other than the delayed shift in the morning has not had any issues. i would like to know where the thermostat is that controls the temperature of the tranny

[Transient]

On 4/18/2025 at 7:48 AM, Srode1 said:

I don't know of any issues with 8 speeds that left lots of trucks incapacitated waiting on parts for months at dealers do you?  Once the updated fluids are put in and in some cases a new torque converter the they have no issues with the exception of an occasional clunky shift, that's been my experience and what I've read regardless of any class action that's unresolved.   

 

You might be thinking it's just diesel because that's where the safety recall was initiated 

 

Oooh, a biased 3rd party source.  Puhleez!    Stop pretending that I said the 10-speed was perfect.  Scroll up and you won't find that I ever said that.  Right now, the difference between the 8 speed and the 10 speed is time.  8 speed has been around longer, so it's had more time for the bugs to be worked out.  As for me, (i hope you're paying attention @newdude), 2020 with the 6.2 that has 80,000+ miles and no issues.

 

Since @newdudeseems to an expert at all things automotive due to his numerous comments about all the other vehicle makes and models out there, I have a question.  Is the 8 speed in the new Toyota Tacoma and 4Runner the same is what's in the Colorado/Silverado/Sierra?  I've seen reports of major issues in the Tacoma, including failure.  Iirc, both GM and Toyota are being supplied by Aisin.

 

What's really sad about this is your hurt feelings have taken this thread off topic.  If you're going to make an inaccurate statement, expect to get a response. 

Edited April 20 by Transient

[newdude]

4 minutes ago, Transient said:

Oooh, a biased 3rd party source.  Puhleez!    Stop pretending that I said the 10-speed was perfect.  Scroll up and you won't find that I ever said that.  Right now, the difference between the 8 speed and the 10 speed is time.  8 speed has been around longer, so it's had more time for the bugs to be worked out.  As for me, (i hope you're paying attention @newdude), 2020 with the 6.2 that has 80,000+ miles and no issues.

 

Since @newdudeseems to an expert at all things automotive due to his numerous comments about all the other vehicle makes and models out there, I have a question.  Is the 8 speed in the new Toyota Tacoma and 4Runner the same is what's in the Colorado?  I've seen reports of major issues in the Tacoma.  Iirc, both GM and Toyota are being supplied by Aisin.

 

 

No.  Toyota uses Aisin, a company that is between Toyota Motor Corporation and Toyota Industries owns 32.48% of the company.  

 

The 8L90 is a GM product.  It is not made by Aisin, nor is it made by ZF.  8L90 8-Speed Automatic Transmission | GM Powered Solutions

 

Quote

Designed and built by GM, the 8L90 automatic transmission offers increased efficiency and lighter weight compared to the previous 6L90 Hydra-Matic six speed transmissions. With a wide 7.0 overall gear ratio, smaller steps between gears, and numerically higher 4.56 first gear, the 8L90 (AH2R) helps keep the engine within the sweet spot of the rpm band for a greater feeling of immediate performance while making the most of its horsepower and torque to optimize performance and efficiency. Vehicle control features including Grade Braking and Driver Shift Control (TAP Shift) are available based on application needs.

 

 

10 speed RWD and the 8/9 speed FWD are the GM/Ford collaboration transmissions.  They share fluid and many if not most all of the hard parts, tuning and software is brand specific.  

[Transient]

3 minutes ago, newdude said:

 

 

No.  Toyota uses Aisin, a company that is between Toyota Motor Corporation and Toyota Industries owns 32.48% of the company.  

 

The 8L90 is a GM product.  It is not made by Aisin, nor is it made by ZF.  8L90 8-Speed Automatic Transmission | GM Powered Solutions

 

 

 

10 speed RWD and the 8/9 speed FWD are the GM/Ford collaboration transmissions.  They share fluid and many if not most all of the hard parts, tuning and software is brand specific.  

Thanks for the answer. 

 

Is GM still using an accumulator on the auto start/stop 8 speed trucks with the 2nd gen trans like the current Colorado, instead of the electrical pump to keep the trans lines pressurized like on the 10 speed?

[newdude]

1 hour ago, Transient said:

Thanks for the answer. 

 

Is GM still using an accumulator on the auto start/stop 8 speed trucks with the 2nd gen trans like the current Colorado, instead of the electrical pump to keep the trans lines pressurized like on the 10 speed?

 

 

8L80 (gen II 8 speed) uses a electric/hydraulic aux pump.  It can prime like the fuel pump does when you open the doors to pre-fill.

 

ATRA article on the gen 2 upgrades - Gears Magazine - What's That Noise? GM 8-Speed Generation II

[GMCustomerService]

On 4/19/2025 at 9:06 AM, silveradosid said:

2020 2.7 with the 8 speed has 95k miles and other than the delayed shift in the morning has not had any issues. i would like to know where the thermostat is that controls the temperature of the tranny

Have you made your GM dealer of your concern? If not, we are happy to help, and ask that you reach out via email at [email protected]. 

[4banger]

On 4/18/2025 at 6:51 AM, newdude said:

 

 

Pretty much.  We've opened up way more 10 speeds than 8s.  

 

I'd take an 8 over a 10 right now until they get their act together.  34,000mi on my 22.5 2.7 HO and 8 speed, that transmission has given me zero issues so far.  

 

48,000 miles on my 22.5 2.7 HO 8spd and no issues at all. It tows almost full time now that I commute in a little maverick. 4” lift, and lots of 4wd required for primarily hunting and fishing duty. Around 900 lbs of fuel and tools and gear added to truck and low 3000 lb range on adventure built lifted alum cargo trailer. 

[4banger]

Can’t make v8 small enough for boost in half tons. Gotta be half the displacement because that’s what one turbo does for moving air, it’s like a whole bank of cylinders you can fit in your hand.

 

I can live without the subjective attribute of sound of a v8, I was over my last 5.3 in a couple weeks, now a few years in on the turbo and smile and love the sound every day still.
 

And it’s a stealth bomber for hunting and scouting and early morning campground polite etc. Game changer for this outdoorsman. 

[BIGDOGx]

On 9/5/2024 at 1:20 PM, ScathaTheWorm said:

 

DOD IS NOT GOING ANYWHERE. It will be to stay, and maybe you do not realize that IF they removed it, they would be FINED HEAVILY...so they have to keep it. Only thing I would ask is a better and stronger bearings and tighter and more robust lifters.  DOD is a maintenance issue...neglect it and it will make you pay. Even in Qatar here we have it...and it is illegal to disable it.

 

Other manufacturers such as Toyota have had PLENTY of debacles....and GMC/Chevrolet is no different from them. They still sold large numbers in the Middle east, even with the beating they took. 

 

1. Make the 5.3 V8 with 380-400 hp minimum

2. The 6.2 must be updated to have 440-470 or just under 500 hp. 

 

 

It is not illegal to disable that junk technology here in America. It is also well proven that this junk technology that GM has damaged their reliability with, also provides 0 increase in fuel efficiency. Not some but EVERYONE i have talked with regarding range devices claim they see a 0% decrease in mileage when it is disabled, meaning all it does is destroy engines and provides 0 benefit of increased  fuel efficiency.

Edited April 22 by BIGDOGx

[KARNUT]

1 hour ago, BIGDOGx said:

It is not illegal to disable that junk technology here in America. It is also well proven that this junk technology that GM has damaged their reliability with, also provides 0 increase in fuel efficiency. Not some but EVERYONE i have talked with regarding range devices claim they see a 0% decrease in mileage when it is disabled, meaning all it does is destroy engines and provides 0 benefit of increased  fuel efficiency.

GM actually admitted it didn’t do much when there was a chip shortage. They sold trucks without them being able to cylinder deactivate. The guts were there. Not the chips to deactivate. If memory serves they said 1/2 to 1 mile per gallon at best. I believe they rebated 50$. During my testing on my truck I got 1/2 mile per gallon at 72 miles per gallon with it on. I will never buy a GM with it. I have it on the odyssey. But it didn’t cost me anything.