Wishful Thinking? (2014 Transmission)

Howdy, Boys: I recently got a 2014 with 31,000 miles and bought a Superior thermostat bypass kit to lower the transmission temp, which I heard was a GM attempt to increase mileage at the expense of slow-cooking the transmission. Anyway, I went to get the kit installed at my local transmission shop (I'm too old to get under a vehicle) and they handed the kit back to me and told me my vehicle did not have the thermostat set-up in my cooling lines. They also told me I was fortunate that I did not have the thermostat; that my transmission might actually last a while.
Next, I was at my local repair shop getting an oil change and the service manager, whom I know, told me I may "dodge a bullet" if my 2014 was "early enough"; that the really frequent transmission failures happened mid-2014 and newer. (My vehicle was built 09/13.)
Finally, in the last month I have met two different Tahoe owners - one of which said he has 187,000 miles on his 2012 Tahoe with no transmission failures, nor modifications, and the other has a 2011 with 211,000 miles and no transmission issues, or mods.
Question: Is there something to this - that earlier pre-thermostat 6L80 units typically last longer than later 2014 and newer transmissions with the thermostat? Thanks. I enjoy this website.

The thermostat can stick and cause problems.

Our models shouldn't have one, I believe it's the next generation that got the thermostat.

The later years are more updated/better, but if there is something specific to mid-2014? I don't know.
Perhaps the new pickups that came out that year and have a thermostat?

With the kind of mileage you got, I might change the fluid and not worry about it for quite some time!

Lil Timmy Shy said:

Howdy, Boys: I recently got a 2014 with 31,000 miles and bought a Superior thermostat bypass kit to lower the transmission temp, which I heard was a GM attempt to increase mileage at the expense of slow-cooking the transmission. Anyway, I went to get the kit installed at my local transmission shop (I'm too old to get under a vehicle) and they handed the kit back to me and told me my vehicle did not have the thermostat set-up in my cooling lines. They also told me I was fortunate that I did not have the thermostat; that my transmission might actually last a while.
Next, I was at my local repair shop getting an oil change and the service manager, whom I know, told me I may "dodge a bullet" if my 2014 was "early enough"; that the really frequent transmission failures happened mid-2014 and newer. (My vehicle was built 09/13.)
Finally, in the last month I have met two different Tahoe owners - one of which said he has 187,000 miles on his 2012 Tahoe with no transmission failures, nor modifications, and the other has a 2011 with 211,000 miles and no transmission issues, or mods.
Question: Is there something to this - that earlier pre-thermostat 6L80 units typically last longer than later 2014 and newer transmissions with the thermostat? Thanks. I enjoy this website.

Click to expand...

no thermostat on the gmt900's
the "weak" spot is the torque converter.
regardless of a 6l80 having a thermostat or not.
typical failures start to show up around 120k, this doesn't mean one will fail at that mileage it's just a known time period when it "could" start to show symptoms
it might go 400k and work perfectly.... no telling

mikez71 said:

The thermostat can stick and cause problems.

Our models shouldn't have one, I believe it's the next generation that got the thermostat.

The later years are more updated/better, but if there is something specific to mid-2014? I don't know.
Perhaps the new pickups that came out that year and have a thermostat?

With the kind of mileage you got, I might change the fluid and not worry about it for quite some time!

Click to expand...

never once heard of a transmission thermostat getting "stuck" where did you get that info? the way it is designed it's just a spring and a ball basically

Well maybe, maybe not! I haven't seen it myself, and there are no numerous claims, so maybe it's just shills.

At the bottom is an excerpt where someone claims it, also this company selling a bypass kit, so take it with a grain..

"The OEM part has restrictive internal passages. When the OEM valve fails in the closed position, transmission fluid doesn’t reach your cooler. This can be caused by mechanical failure or debris. The result of stock valve failure can cause the transmission to dangerously overheat. Without properly cooled transmission fluid, the demands of towing and rigorous stop-and-go driving conditions shorten the life of transmission components. The PPE Bypass Valve eliminates the extremely restrictive mechanical factory valve, maximizing fluid flow to and from the transmission cooler."

Photos of valve from this thread..



--

"Yes I deal with the stock ones everyday. Im a world class tech for GM at a Chevy dealership. The converters on stock applications fail because they are designed to lock up in every gear after 2014. They are pulse width controlled, even on the 8L90 and so on. the new redesigned trans cooler lines have an updated thermostat valve that opens at 140 instead of 192. I have seen a LOT of failed units because that valve didnt open or was stuck. Im thinking on mine, my converter is slowly starting to die. Usually on the stock trucks, youd start to get a shudder. Im not getting that, so it confused me."
--

world class tech for gm at a chevy dealership.

yeah he totally lost me there.

If you watch the tach. you'll notice the rpms vary a couple hundred rpms up and down depending on the load and throttle, and cylinder de-activation. That's the lock-up converter slipping as programmed for the smoothest operation that soccer moms demand. That lock-up clutch doesn't seem to be designed to last with that programmed slip.

07-14 is the New, new Body Style Full size SUV (NNBS / GMT 900) Tahoe, Burb, Yukon & Escalade

2007.5 -13 is the New, new Body Style Pick up (NNBS / GMT 900) Silverado & Sierra.

Notice for Pick ups, GM started the Next model version (called K2XX) a year earlier after 2013 vs 2014 for full size SUV.

This means K2XX trucks are 2013-2019.

K2XX full size SUV are 2014-2019.

Because of the shared terminology of a Yukon being referred to as a truck some websites refer to a Yukon only being made from 07-13 if it’s in Denali trim.

That’s because the GMC Sierra also came in Denali trim as a Pick up.

So a 2014 Pick up is considered K2XX and a 2014 full size SUV is considered a NNBS.

A 2014 K2XX GMC Sierra Denali would have the transmission cooler, the 2013 NNBS Sierra Denali would NOT have a transmission cooler because only K2XX trucks and full size SUV got them.

Your vehicle is a NNBS so it didn’t have the transmission cooler GM began adding in the K2XX.

Ez Pz Right?

I always say my year, (OBS is about the only one I can keep straight) those code words confuse me for some reason. In my head I know what years the body styles changed but just can’t keep the code words straight lol

petethepug said:

07-14 is the New, new Body Style Full size SUV (NNBS / GMT 900) Tahoe, Burb, Yukon & Escalade

2007.5 -13 is the New, new Body Style Pick up (NNBS / GMT 900) Silverado & Sierra.

Notice for Pick ups, GM started the Next model version (called K2XX) a year earlier after 2013 vs 2014 for full size SUV.

This means K2XX trucks are 2013-2019.

K2XX full size SUV are 2014-2019.

Because of the shared terminology of a Yukon being referred to as a truck some websites refer to a Yukon only being made from 07-13 if it’s in Denali trim.

That’s because the GMC Sierra also came in Denali trim as a Pick up.

So a 2014 Pick up is considered K2XX and a 2014 pick up is considered a NNBS.

A 2014 K2XX GMC Sierra Denali would have the transmission cooler, the 2013 NNBS Sierra Denali would NOT have a transmission cooler because only K2XX trucks and full size SUV got them.

Your vehicle is a NNBS so it didn’t have the transmission cooler GM began adding in the K2XX.

Ez Pz Right?

Click to expand...

You lost me where you say, "So a 2014 Pick up is considered K2XX and a 2014 pick up is considered a NNBS.". So, it's both?