Faulty Trans Fluid Temp Sensor Special Coverage

midwestdenaliguy · September 15, 2020

Wanted to make everyone aware of a special coverage if you are dealing with a faulty trans fluid temp sensor. I believe this is only for the 8 speed on the 2015 and 2016, but correct me if it applies to the 6 speed or other years as well. The sensor is attached to a wire harness inside your transmission and the original harness has been known to go bad, specifically the temp sensor. I had 2 codes light up the SES, P0700 and P0711. P0711 let's you know it's the sensor. A month and a half ago (7/29/2020), GM released a special coverage that extends the warranty to repair this, up to 10 years or 120,000 miles. It's special coverage #N192291660. They replaced the transmission wire harness (#24298757), the trans pan gasket (#24260071), trans filter (#24274402), and all trans fluid (new HP fluid - #19417577B). Additionally, it covers some of the exhaust parts too if they have to remove any to get the trans pan out (my dealer did not have to do this, most can slightly push down on the exhaust to get the pan out). But if your dealer needs to remove any of the exhaust, it's an exhaust seal and gasket that need to be replaced (#15077362 and #15035747).

In addition to the SES light, apparently it can cause hard shifting when the sensor starts to go bad. I didn't experience this, but it's fairly common from what the service dept told me. You can also easily tell when the sensor is going bad by watching your trans fluid temp needle. It will erratically bounce up and down, sometimes slightly and other times it's big jumps.

My 2016 GMC Sierra has the 6.2L paired with the 8 speed trans. Had this repair done under the special coverage extended warranty with 112,600 miles on my odometer. They got me in and out the same day.

Edited September 25, 2020 by midwestdenaliguy

CadillacLuke24 · September 16, 2020

THANK YOU! I don't yet have codes, but I do have the hard shifts and the erratic trans temp gauge behavior...My Cadillac behaved similarly when her trans harness went out. Headed to the dealer later today! Thank you again!

16sierra · September 19, 2020

FYI for anyone reading this thread, this only applies to the 6.2L + 8 speed. No luck on the 5.3L + 8 speed.

martha3065 · September 19, 2020

FYI for anyone reading this thread, this only applies to the 6.2L + 8 speed. No luck on the 5.3L + 8 speed.

WTF? They must have used different sensors and harnesses in those attached to a 5.3, or the torque of the 6.2 causes problems in these electronic parts (LOL). Those with the 5.3 have the same issue. SMDH.

16sierra · September 19, 2020

33 minutes ago, martha3065 said:

9 hours ago, 16sierra said:

FYI for anyone reading this thread, this only applies to the 6.2L + 8 speed. No luck on the 5.3L + 8 speed.

WTF? They must have used different sensors and harnesses in those attached to a 5.3, or the torque of the 6.2 causes problems in these electronic parts (LOL). Those with the 5.3 have the same issue. SMDH.

It's probably because most of the 6.2L are in Denalis and those are the high margin trucks. Keep the smaller, high margin customer base happiest.

From my perspective, they gaslighted me (and countless others) on the transmission issues until I was out of powertrain warranty, but then they are happy to charge hundreds to thousands to do what they wouldn't under warranty. Service advisors who lie to my face about what a procedure involves or that these trucks don't have a trans fluid filter. They just assume everyone that comes in the door is an idiot, but they need to start accepting that more information than ever is available online. I'll fix it myself even if I only save $100 just to not reward their scammy behavior.

This was linked in another thread, but I would recommend this video for a how-to:

As he states in the video, the harness part # is 24298757. I'd also recommend a filter TF922. The pan gasket is supposed to be reusable but is part # 24260071 if you want to replace that.

Edited September 19, 2020 by 16sierra

CadillacLuke24 · September 21, 2020

Filter is a good idea, though reusing a filter at all seems odd.

New temp sensor is in. Already noticed, while warming up the truck to check trans fluid levels, the temp gauge is much more linear and consistent. Gradual and measured temp increases, whereas the old one would rise, drop a few degrees, come back up, stop, drop again, then continue to climb. VERY excited to see how he drives, cause I bet it will be very noticeable improvement!

CadillacLuke24 · September 23, 2020

WOW.

Shifts are massively improved. There's a tad of 1-2 crispness, but ALL shifts are exponentially better. After the initial startup there was NO firm shifts. Once up to temp they are a bit firmer, but I was driving up Casper Mountain, back down, and in a quite spirited manner, so I'm counting it as an absolute victory.

Once massive improvement is that the lag has disappeared. Prior to service he would consider my imput of increased throttle for a few seconds, then bump down a gear in a firm fashion. The lag is gone and the shifts are noticeably smoother.

He seems to run warmer, temps got right up to the 180s-190s and stayed there. Again, climbing the mountain and coming back down like I was late for my wedding probably contributed to that, but even then that's not the danger zone.

I fully expect shifting performance to continue to improve as the new part settles in. These are initial impressions in the first 50 miles.

Thank you so much for sharing this info. I feel like I have my truck back. The shifting was not interfering with function, but driveability was hampered to the point I was more worried about breaking something than enjoying my truck.

midwestdenaliguy · September 24, 2020

On 9/23/2020 at 3:45 AM, CadillacLuke24 said:

WOW.

Shifts are massively improved. There's a tad of 1-2 crispness, but ALL shifts are exponentially better. After the initial startup there was NO firm shifts. Once up to temp they are a bit firmer, but I was driving up Casper Mountain, back down, and in a quite spirited manner, so I'm counting it as an absolute victory.

Once massive improvement is that the lag has disappeared. Prior to service he would consider my imput of increased throttle for a few seconds, then bump down a gear in a firm fashion. The lag is gone and the shifts are noticeably smoother.

He seems to run warmer, temps got right up to the 180s-190s and stayed there. Again, climbing the mountain and coming back down like I was late for my wedding probably contributed to that, but even then that's not the danger zone.

I fully expect shifting performance to continue to improve as the new part settles in. These are initial impressions in the first 50 miles.

Thank you so much for sharing this info. I feel like I have my truck back. The shifting was not interfering with function, but driveability was hampered to the point I was more worried about breaking something than enjoying my truck.

That's awesome to hear. I've had countless members help me so I try to return the favor when I can. Safe travels and enjoy the 'new' truck!

midwestdenaliguy · September 25, 2020

FYI - I updated the original post to include the trans filter part number and the exhaust part numbers (though removal of the exhaust isn't necessary - but up to you if you want them replaced). I also edited it to remove that I had my dealership reuse my trans filter because they didn't have it in stock at the time (they had recently replaced it as part of a triple flush cleaning). My dealership called me and said they got more in stock and wanted to replace mine to be safe, just had that done yesterday.

mookdoc6 · September 25, 2020

This is correct I proclaimed few years ago that the Internal trans temp sensors were causing many people with awful shifting behavior and no it does not always throw a code. That and the 6pin MAFS which obviously is incorrect for air density with low moisture content. What do I know....

6.2L transmission issues · September 26, 2020

Is there a way for me to see the special coverage note? I'm having this issue and was told there was no special coverage. I have a 2015 Sierra with the 6.2L. I was quoted at $1225.

midwestdenaliguy · September 27, 2020

23 hours ago, 6.2L transmission issues said:

Is there a way for me to see the special coverage note? I'm having this issue and was told there was no special coverage. I have a 2015 Sierra with the 6.2L. I was quoted at $1225.

Give them the special coverage number, N192291660, and have them print it off for you. For some reason it's not easy to find using google. Did they specify that they don't see that special coverage or is it that your vehicle is not covered under it? If the latter, I am curious as to why.

lucas287 · October 30, 2020

Just FYI to anyone out there in my boat. I never received a letter, but, I'm also the second owner of my truck. I figured WTH may as well call the dealer and see if I'm covered. BINGO! He said yep, you're covered. Scheduled to have it done next week! For the record, I've never thrown a code or had erratic trans temp readings. I'm primarily doing this to get a fresh filter and new fluid. My expectations are low though as to how it will react.

They're also going to assess my motor mounts under that TSB and maybe I'll get some new ones under my CPO warranty.

CaptStoots · January 14, 2021

Has anyone with a 5.3lt truck successfully gotten this special coverage applied outside of an extended warranty? It boggles my mind how only the 6.2 is covered while the 5.3 has the same 8 speed transmission and obviously has the same issues.

Flip07AWD · March 26, 2021

On 9/26/2020 at 10:11 AM, 6.2L transmission issues said:

Is there a way for me to see the special coverage note? I'm having this issue and was told there was no special coverage. I have a 2015 Sierra with the 6.2L. I was quoted at $1225.

My 2015 All Terrain 6.2L just started throwing this code sadly 2 months out of warranty.

Where you able to get it covered under the special warranty?