Another 6L80 FAILED!

PhilGMCYukon · April 12, 2024

Hello everyone,

I own a 2019 Yukon 5.3 4x4. (70k miles) The dreaded transmission slippage has hit my vehicle. It has become relatively undriveable. I can accelerate it to speed but slowly to allow the transmission to engage gears. I took the vehicle to an independent shop who told me they had some computer tool to manually control the transmission (never heard of such a tool), and there is an internal failure. They want $3600 to take it apart and try to fix the problem. I'd rather not let anyone start taking things apart. Took to GMC service center, and they deemed the transmission faulty and and want to replace it $6500. The warranty went out last October. I tried to petition GM for cost assistance since its barely out of warranty, and they will only help if the dealer will also provide some kind of cost assistance. Dealer said without a transmission maintenance record, I can kick rocks.

Since this issue has come up, I see online now ongoing issues with this transmission with overheating. A service bulletin was released in 2021 about the trans Thermal Bypass Valve. It seems my transmission has been running super hot, and now its cooked. Anyone have any advice on how to petition the dealer or manufacture to fix this??

KARNUT · April 13, 2024

3 hours ago, PhilGMCYukon said:

Hello everyone,

I own a 2019 Yukon 5.3 4x4. (70k miles) The dreaded transmission slippage has hit my vehicle. It has become relatively undriveable. I can accelerate it to speed but slowly to allow the transmission to engage gears. I took the vehicle to an independent shop who told me they had some computer tool to manually control the transmission (never heard of such a tool), and there is an internal failure. They want $3600 to take it apart and try to fix the problem. I'd rather not let anyone start taking things apart. Took to GMC service center, and they deemed the transmission faulty and and want to replace it $6500. The warranty went out last October. I tried to petition GM for cost assistance since its barely out of warranty, and they will only help if the dealer will also provide some kind of cost assistance. Dealer said without a transmission maintenance record, I can kick rocks.

Since this issue has come up, I see online now ongoing issues with this transmission with overheating. A service bulletin was released in 2021 about the trans Thermal Bypass Valve. It seems my transmission has been running super hot, and now its cooked. Anyone have any advice on how to petition the dealer or manufacture to fix this??

Transmission service record? Did things change with newer models? Before I joined this website and knew better. The owners manual would say transmission fluid change could be anywhere from 100K to 150K. My last truck an older one didn’t get its first fluid change until 165K when I bought it. It still happily shifting at 184K. Are they saying you should have followed the severe service maintenance? Wouldn’t that be 60K miles? Sounds like hair splitting to me. Good luck.

CMoore711 · April 18, 2024

I agree with @Karnut with only 70K miles I would push back on the dealer.

Owners manual says "normal" maintenance first transmission fluid service is at 97.5K miles.

"Severe" maintenance schedule first transmission fluid service is at 47.5K miles and 2nd one at 90K miles.

There may be an argument that based on normal use (no towing) at 70K miles you wouldn't have serviced the transmission yet. So you can ask the dealer at only 70K miles what type of transmission maintenance record should exist? No matter what their answer is tread lightly with a "non-confrontational approach".

"Well I was reviewing my owners manual in the Service and maintenance section and it states here on page 397 in the Maintenance Schedule for Normal use, which is what I follow since I don't tow or anything with it, and the first transmission fluid service doesn't need to occur until I'm at 97.5K miles? So if I'm operating my vehicle normally based on the manufacturer's recommendation why would I have a transmission service prior to 97.5K miles?". Then service guy may down the Sever Maintenance schedule rabbit hole and then I'd simply say "But I don't use my vehicle for any "severe duty" use; I don't tow or haul anything it's simply a family kid hauler."

That being said a lot of this will be based on your relationship with the dealer and it will still be at their discretion. Personally, I wouldn't count on much coming out of that conversation.

Being that your out of warranty I also wouldn't put the a GM remanufactured 6l80 transmission back in it either. Find a good reputable transmission builder that knows the 6l80 specifically (they exist), have one built for you with upgraded clutch packs, stronger than normal/OE parts, no thermal bypass valve so it runs cooler, and a billet torque converter at stock stall speed and call it a day. You'll still be in the $6,500 +/- range. Then start changing the transmission fluid and filter every 45-50K miles. It's a $500 service that will extend the life of your $6,500 transmission significantly. And at the rate you drive with a 2019 with only 70K miles $500-$600 every 3-4 years for proactive maintenance is nothing.

Edited April 18, 2024 by CMoore711

Grumpy Bear · April 20, 2024

On 4/18/2024 at 10:32 AM, CMoore711 said:

I agree with @Karnut with only 70K miles I would push back on the dealer.

Owners manual says "normal" maintenance first transmission fluid service is at 97.5K miles.

"Severe" maintenance schedule first transmission fluid service is at 47.5K miles and 2nd one at 90K miles.

There may be an argument that based on normal use (no towing) at 70K miles you wouldn't have serviced the transmission yet. So you can ask the dealer at only 70K miles what type of transmission maintenance record should exist? No matter what their answer is tread lightly with a "non-confrontational approach".

"Well I was reviewing my owners manual in the Service and maintenance section and it states here on page 397 in the Maintenance Schedule for Normal use, which is what I follow since I don't tow or anything with it, and the first transmission fluid service doesn't need to occur until I'm at 97.5K miles? So if I'm operating my vehicle normally based on the manufacturer's recommendation why would I have a transmission service prior to 97.5K miles?". Then service guy may down the Sever Maintenance schedule rabbit hole and then I'd simply say "But I don't use my vehicle for any "severe duty" use; I don't tow or haul anything it's simply a family kid hauler."

That being said a lot of this will be based on your relationship with the dealer and it will still be at their discretion. Personally, I wouldn't count on much coming out of that conversation.

Being that your out of warranty I also wouldn't put the a GM remanufactured 6l80 transmission back in it either. Find a good reputable transmission builder that knows the 6l80 specifically (they exist), have one built for you with upgraded clutch packs, stronger than normal/OE parts, no thermal bypass valve so it runs cooler, and a billet torque converter at stock stall speed and call it a day. You'll still be in the $6,500 +/- range. Then start changing the transmission fluid and filter every 45-50K miles. It's a $500 service that will extend the life of your $6,500 transmission significantly. And at the rate you drive with a 2019 with only 70K miles $500-$600 every 3-4 years for proactive maintenance is nothing.

I have 243,000 miles on a GM Ecotec 2.4 Oil burner. Local dealer told me that at this number of miles people are generally on their third motor. So, he asked me how I got just ONE to go that far?

Answer?

With zero help from GM!

Protect the transmission, not the warranty.

:idiot:

Edited April 20, 2024 by Grumpy Bear

newdude · April 24, 2024

On 4/12/2024 at 5:30 PM, PhilGMCYukon said:

Hello everyone,

I own a 2019 Yukon 5.3 4x4. (70k miles) The dreaded transmission slippage has hit my vehicle. It has become relatively undriveable. I can accelerate it to speed but slowly to allow the transmission to engage gears. I took the vehicle to an independent shop who told me they had some computer tool to manually control the transmission (never heard of such a tool), and there is an internal failure. They want $3600 to take it apart and try to fix the problem. I'd rather not let anyone start taking things apart. Took to GMC service center, and they deemed the transmission faulty and and want to replace it $6500. The warranty went out last October. I tried to petition GM for cost assistance since its barely out of warranty, and they will only help if the dealer will also provide some kind of cost assistance. Dealer said without a transmission maintenance record, I can kick rocks.

Since this issue has come up, I see online now ongoing issues with this transmission with overheating. A service bulletin was released in 2021 about the trans Thermal Bypass Valve. It seems my transmission has been running super hot, and now its cooked. Anyone have any advice on how to petition the dealer or manufacture to fix this??

The original TBV was correct at the time the truck was built. It full opened at 194F and that was the normal operating temperature as designed.

GM determined due to the mass amount of torque converter failures (which mostly a design of the converter issue rather than the heat but the heat doesn't help as it shortens fluid life) that 194F was "too hot" and lowered it to 158F full open on the new thermostat.

You will probably get nowhere with GM on it if the dealer won't help on assistance. This is why its always important to keep records if you are trying for work under warranty or for customer assistance just outside of warranty.

cbarn · July 11, 2024

On 4/24/2024 at 5:19 PM, newdude said:

The original TBV was correct at the time the truck was built. It full opened at 194F and that was the normal operating temperature as designed.

GM determined due to the mass amount of torque converter failures (which mostly a design of the converter issue rather than the heat but the heat doesn't help as it shortens fluid life) that 194F was "too hot" and lowered it to 158F full open on the new thermostat.

Sorry to re-open this thread after a few months, but I'm in a similar situation - used 2018 Suburban (bought with 96K miles on it) just came back from the shop after the torque converter shredded itself and shot metal through the transmission. Fortunately I'd purchased it with an extended warranty specifically because I'd seen issues at about 100K with transmissions, so the full replacement at the dealer was covered. What I don't know, though, is whether the new transmission (a rebuild) would have the lowered thermostat - driving home by a rather circuitous route (but no highway) I didn't see temp exceed 162F (and it's a 93F day). Any way to check this?

newdude · July 13, 2024

On 7/11/2024 at 7:08 PM, cbarn said:

Sorry to re-open this thread after a few months, but I'm in a similar situation - used 2018 Suburban (bought with 96K miles on it) just came back from the shop after the torque converter shredded itself and shot metal through the transmission. Fortunately I'd purchased it with an extended warranty specifically because I'd seen issues at about 100K with transmissions, so the full replacement at the dealer was covered. What I don't know, though, is whether the new transmission (a rebuild) would have the lowered thermostat - driving home by a rather circuitous route (but no highway) I didn't see temp exceed 162F (and it's a 93F day). Any way to check this?

It the work was done at the dealer, you should have the part #s of what was installed on the truck on your paperwork. 85585333 is the number.

The other method is crawl under it and see if you see "70" stamped in the TBV.

Chances are pretty high the dealer installed it because of the TSB for the TBV, and your temps on a hot day sound about right for the new one being installed.

MaverickZ71 · July 13, 2024

3 hours ago, newdude said:

It the work was done at the dealer, you should have the part #s of what was installed on the truck on your paperwork.  85585333 is the number.

The other method is crawl under it and see if you see "70" stamped in the TBV.

Chances are pretty high the dealer installed it because of the TSB for the TBV, and your temps on a hot day sound about right for the new one being installed.

At the last 2 GM dealers I was at, they no longer give you that backup paperwork showing part numbers, labor hours, fluids/quantities, shop supplies, etc. They have it printed out, but they don't let you have it. You sign a single page cover sheet that you are paying $X and accepting your vehicle as is after they performed X service, and then you get an unsigned, simplified copy of that one sheet back. If you had 6 services performed, it shows a half-assed description of only the first thing they did. When I said hey, we used to get all of those backup details, the Service Mgr smirked and said yeah, and labor used to be $75 an hour, too, and closed the window.

Edited July 13, 2024 by MaverickZ71

Tusz · November 27, 2024

On 4/12/2024 at 5:30 PM, PhilGMCYukon said:

Hello everyone,

I own a 2019 Yukon 5.3 4x4. (70k miles) The dreaded transmission slippage has hit my vehicle. It has become relatively undriveable. I can accelerate it to speed but slowly to allow the transmission to engage gears. I took the vehicle to an independent shop who told me they had some computer tool to manually control the transmission (never heard of such a tool), and there is an internal failure. They want $3600 to take it apart and try to fix the problem. I'd rather not let anyone start taking things apart. Took to GMC service center, and they deemed the transmission faulty and and want to replace it $6500. The warranty went out last October. I tried to petition GM for cost assistance since its barely out of warranty, and they will only help if the dealer will also provide some kind of cost assistance. Dealer said without a transmission maintenance record, I can kick rocks.

Since this issue has come up, I see online now ongoing issues with this transmission with overheating. A service bulletin was released in 2021 about the trans Thermal Bypass Valve. It seems my transmission has been running super hot, and now its cooked. Anyone have any advice on how to petition the dealer or manufacture to fix this??

Hey Phil and everyone, another one bites the dust. 98k miles 2019 Yukon. Mine is doing the exact same as what you described. What a shame. 5 years old and bought it brand new….Was curious what you ended up doing and how your trans has been, Phil?. Mines getting rebuilt Monday from a shop that knows these and I’m getting a billet convertor. I’m gonna bring up to him about the TSB about the thermostatic bypass valve for the 6L80. Effectively lowering the thermostatic valve operational temperature at 150 degrees instead of 190. Is that something I should definitely have done?. Another question I have is with going forward with a new rebuilt trans without the oem convertor, would it be wise to to delete the AFM on the engine?. I’ve read in other places that does not help these transmission

Edited November 27, 2024 by Tusz

mikemcclain8 · December 16, 2024

While I can't speak directly to the question about AFM delete, I can say that I bought a '15 suburban with 60,000 miles on it and immediately put in the Range to delete AFM. I made it to 229,000 miles before the transmission blew up. So, maybe it helps as the transmission guy told me they often go out between 100-150k.

swathdiver · December 17, 2024

On 4/12/2024 at 5:30 PM, PhilGMCYukon said:

Hello everyone,

I own a 2019 Yukon 5.3 4x4. (70k miles) The dreaded transmission slippage has hit my vehicle.

It's been almost a year now Phil, what's the outcome to this story?

diyer2 · December 17, 2024

Trans fluid changes makes a lot of sense to me, and using better fluid.

BIGDOGx · December 19, 2024

On 12/17/2024 at 7:06 AM, diyer2 said:

Trans fluid changes makes a lot of sense to me, and using better fluid.

I dont get why the manual states the wrong advice of 100k intervals, no one should go 100k on the original trans oil. That is literally begging to have premature trans failure imo. I would say 50 or a bit under if you tow, and 60-65k if you dont and im talking a real service with dropping the pan and changing the filter.

swathdiver · December 20, 2024

13 hours ago, BIGDOGx said:

I dont get why the manual states the wrong advice of 100k intervals, no one should go 100k on the original trans oil. That is literally begging to have premature trans failure imo. I would say 50 or a bit under if you tow, and 60-65k if you dont and im talking a real service with dropping the pan and changing the filter.

Almost everybody's driving habits fall under the severe service category. The interval is about 45K miles for that year.

I had my transmission fluid analyzed at 36K and they said it had 10K of life left in it. We now change it between 36-40K or so, sooner if we've done any towing of substance.

Redesigning the cooling system and using that thermostat on the side of the transmission condemned many of them to a service life of only about 100K miles. They also had condenser issues because of this. Sometimes newer ain't better.