Jump to content

Letter from GMC today re rough trans & hesitation on 6.2L engines

Linecapt
 Share

Recommended Posts

Linecapt Enthusiast

Linecapt

Posted
Posted (edited)

I got a letter in the mail today from GMC regarding my 2016 Sierra with the 6.2L engine that "may have a condition that affects the electrical connection to the transmission oil temperature sensor.  If this condition occurs, rough transmission shifts or hesitation during acceleration may occur.  Additionally, the Malfunction Indicator Light (Check Engine Light) would illuminate and a diagnostic trouble code related to the temperature sensor would set."  They're extending protection to 10 years or 120000 miles.  

 

Has anyone else with the 6.2L engine received this letter?  Does anyone think this relates to what everyone always complained about, the rough shifts and the hesitations that we've long complained of?  

Edited by Linecapt
Link to comment
Share on other sites
mookdoc6 Senior Enthusiast

mookdoc6

Posted
Posted
On 9/2/2020 at 6:09 PM, Linecapt said:

I got a letter in the mail today from GMC regarding my 2016 Sierra with the 6.2L engine that "may have a condition that affects the electrical connection to the transmission oil temperature sensor.  If this condition occurs, rough transmission shifts or hesitation during acceleration may occur.  Additionally, the Malfunction Indicator Light (Check Engine Light) would illuminate and a diagnostic trouble code related to the temperature sensor would set."  They're extending protection to 10 years or 120000 miles.  

 

Has anyone else with the 6.2L engine received this letter?  Does anyone think this relates to what everyone always complained about, the rough shifts and the hesitations that we've long complained of?  

I have surmised that from the beginning the junk wiring harnesses on 2015-2016 on 5.3/6.2 8L90 Transmissions along with the super fancy 6 pin MAF sensors that are so sensitive to Dry,Humid air and their corresponding densities and temperatures.....Got a Crap 8L90?  Drive it in the rain and report back....Yeah, it's coupled with Hygroscopic oil which amplified the drive-ability issues.   GM can't figure out what day the trans drives better astonishing.....but hey?  nobody listens to me....................

Link to comment
Share on other sites
Grumpy Bear Senior Enthusiast

Grumpy Bear

Posted
Posted
5 minutes ago, mookdoc6 said:

I have surmised that from the beginning the junk wiring harnesses on 2015-2016 on 5.3/6.2 8L90 Transmissions along with the super fancy 6 pin MAF sensors that are so sensitive to Dry,Humid air and their corresponding densities and temperatures.....Got a Crap 8L90?  Drive it in the rain and report back....Yeah, it's coupled with Hygroscopic oil which amplified the drive-ability issues.   GM can't figure out what day the trans drives better astonishing.....but hey?  nobody listens to me....................

You sound like my dad. His favorite is, "But hey don't listen to me, I'm just a dummy". You two should meet. :) 

  • Like 1
Link to comment
Share on other sites
martha3065 Enthusiast

martha3065

Posted
Posted



 Does anyone think this relates to what everyone always complained about, the rough shifts and the hesitations that we've long complained of?  


I doubt it is the cause of all the complaints. Mine has had those symptoms since nearly new, as does a buddy's. Probably gets worse under this condition. I do think this is the same issue members have posted on here: https://www.gm-trucks.com/forums/index.php?/topic/224729-Money-Light-on-8-Speed,-P0700+P0711
Link to comment
Share on other sites
Ltz4 me? Enthusiast

Ltz4 me?

Posted
Posted

Mine was just fixed b/c of this code on a 16' Silverado 5.3l 8speed m5u tranny.

While the pan was dropped I had them completely drain all bad fluid completely, new tranny filter, new best blue label Mobil 1, new 2 piece wiring harness, transmission relearn.

We will see...it did start shifting really.bad when check engine light came on,( po711)

Transmission temperature sensor was verify ok by the ohm reading taken.

If I can I'm flipping my pill to reduce the oil temperature ( I'm regularly seeing 185-195deg.f)

Link to comment
Share on other sites
elcamino Senior Enthusiast

elcamino

Posted
Posted

185-195ºF is NORMAL operating temp for an automatic transmission.  It runs at peak efficiency at those temps as its DESIGNED to do.  I don't understand why people fell this is bad, its not. Its paranoia.     

  • Haha 1
Link to comment
Share on other sites
mookdoc6 Senior Enthusiast

mookdoc6

Posted
Posted
On 9/4/2020 at 8:10 PM, Grumpy Bear said:

You sound like my dad. His favorite is, "But hey don't listen to me, I'm just a dummy". You two should meet. :) 

Your pops is probably pretty neat guy and holding up well at his age.  Most of my knowledge base is from people of that generation...I reckon there is not much of substance I have learned from the younger folks.  they can put an "APP" on my phone but that's about all...............

  • Like 1
  • Thanks 1
Link to comment
Share on other sites
CadillacLuke24 Enthusiast

CadillacLuke24

Posted
Posted
On 9/5/2020 at 7:05 PM, Ltz4 me? said:

Mine was just fixed b/c of this code on a 16' Silverado 5.3l 8speed m5u tranny.

While the pan was dropped I had them completely drain all bad fluid completely, new tranny filter, new best blue label Mobil 1, new 2 piece wiring harness, transmission relearn.

We will see...it did start shifting really.bad when check engine light came on,( po711)

Transmission temperature sensor was verify ok by the ohm reading taken.

If I can I'm flipping my pill to reduce the oil temperature ( I'm regularly seeing 185-195deg.f)

Do you have a part number for the new 2-piece wiring harness?

Link to comment
Share on other sites
STurner15 Enthusiast

STurner15

Posted
Posted

Got my letter in the mail and took it in immediately. 74k miles 6.2L. They flush the trans with new fluid and replace seals etc etc. have about 20-30miles on the truck now and it seems to run better. But I got a flush around 65k and it worked for a little while... so I am hoping this harness and flush works.... for a .. little while.... longer...

Link to comment
Share on other sites
  • 2 weeks later...
flyingfool Senior Enthusiast

flyingfool

Posted
Posted
On 9/6/2020 at 3:23 AM, elcamino said:

185-195ºF is NORMAL operating temp for an automatic transmission.  It runs at peak efficiency at those temps as its DESIGNED to do.  I don't understand why people fell this is bad, its not. Its paranoia.     

sure, back when a transmission was all mechanical, they could take the heat...  but now they put delicate plastics, seals,  platic check balls and a tcu in the hot boiling transpan.. yeah that will make it reliable, sure!

 

 

Link to comment
Share on other sites
  • 1 month later...
lucas287 Enthusiast

lucas287

Posted
Posted
On 10/30/2020 at 9:24 AM, STurner15 said:

so far so good on my end. added a couple pounds to low end gears shift pressures. smooth and solid still.

Did you do this in HPtuners? If so what table(s) did you change? I'm always tinkering here and there with my tune. 

Link to comment
Share on other sites
  • 2 weeks later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
 Share
Go to topic listing


×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.

  I accept