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Posted

Hey all, new owner to a gorgeous looking truck! I honestly love everything about it... Except how it drives...

 

900 miles on it and it shifts like garbage.

 

Coming to a stop at a stop sign or light get a big clank and jerk. Happens 65% of the time, especially after warmed up. Also has a 25-30% chance of hard up shift when accelerating with a similar jerk. RPMs rev up then shifts with a jerk.

 

Went to dealer and explained issue. Waited almost 2 hours for them to take a 10 minute test drive down the road for them to come back and tell me they couldn't reproduce the problem. Upon questioning the test driver, he explained to me that there was too much transmission fluid (overfilled) and also said there was air pockets in the transmission.... Yea... Ok

 

He also told me he never drove the new 8 speed tranny silverados so he's not sure how the shift should feel, I told him well it definitely should not slam gears or jerk. He said he drained some fluid and released the "air bubbles" so it should be all set and if I have any more issues to bring it back.

 

Drove it home, it happened every time I came to a stop.

 

I'm afraid of the incompetence of the mechanics at this dealer; to try to tell me it's "overfilled and has air bubbles" as to the leading cause of slamming shifts... It's a brand new truck has 900 miles on it, bought it a month ago.

 

I see plenty of people having issues on their 15-16s with this issue and wonder has anyone had any type of resolution? Why is my brand new $60k truck already in need for transmission service?

 

Owned a 97 C2500 and a 00 K3500 and never had an issue with transmission even with almost 200k miles on each of them.

 

Please help!

 

Thank you!

Posted

please read my thread completely, it has all the info on what the dealership "actually" did, there is the transmission fast learn, there's a relearn procedure, and now they've determined to replace the valve body with TCM. So "airbubbles" has nothing to do with it. Just make sure you get EVERYTHING documented, and ALWAYS ALWAYS take the transmission tech or lead tech with you on the drive and show them what it's doing.


At this point, like I mentioned when I PM'd you, deal with the GM Executive Liaison, whose contact info I gave you and go that route.

Posted

900 miles on a truck that needs around 1500-2000 miles for all of the transmission adapt tables to get sorted out. My 2016 All Terrain had firm shifts and weird shifts as well, they pretty much went away by around 1500 miles or so.

Posted

Thanks for all the information, however it's not just a "hard shift" it's a slam/jerk and you can hear the transmission slamming gears, not just feel it. That's normal?

Posted

These transmissions are filled at the transmission assembly plant and normally need no addition/reduction of fluid. On occassion I'm sure it's possible that the vehicle assembly plant might have a need to add/reduce fluid, but as a rule this should be uncommon. Your dealership talked about an "air bubble", there is no "air bubble". If the trans was overfilled it's possible it could create a foaming condition or if underfilled it could cause the lack of suction of fluid but both of those conditions should be extremely rare or non-existent if the oil level is set correctly. Since they removed fluid, a practice that should rarely be required, perhaps you should have them or another dealer recheck the oil level and then adjust it as necessary. It's unlikely, but possible that they removed too much and not that is further adding to you harsh shift concerns.

Posted

Thanks for all the information, however it's not just a "hard shift" it's a slam/jerk and you can hear the transmission slamming gears, not just feel it. That's normal?

Trust me I know what you are dealing with. It's not an oil issue, it's not an air bubble issue. It's a combination of a mechanical/programming in the TCM issue. Either one or the other or both. Email that person I gave you the contact information for, and they should take care of you brother. The slamming is not normal, I questioned myself as to wether it was normal for these transmissions to do what it was doing in our trucks and finally I got enough confirmation that it wasn't.

 

These transmissions are filled at the transmission assembly plant and normally need no addition/reduction of fluid. On occassion I'm sure it's possible that the vehicle assembly plant might have a need to add/reduce fluid, but as a rule this should be uncommon. Your dealership talked about an "air bubble", there is no "air bubble". If the trans was overfilled it's possible it could create a foaming condition or if underfilled it could cause the lack of suction of fluid but both of those conditions should be extremely rare or non-existent if the oil level is set correctly. Since they removed fluid, a practice that should rarely be required, perhaps you should have them or another dealer recheck the oil level and then adjust it as necessary. It's unlikely, but possible that they removed too much and not that is further adding to you harsh shift concerns.

I completely agree as to the fact this isn't the issue. After the one trip doing the transmission fast learn to adjust the clutches that were causing the harsh shift and that didn't work, straight up valve body and TCM right from higher up GM. I think they know that they are some harsh shifting transmissions out there and now they are realizing they actually need new parts or a new TCM

Posted

I don't know about the 8 speed, but I wasn't happy with the way my 6 speed shifted when it had the same mileage, so I removed the negative battery cable for about 30 min. This reset the transmission computer and it settled down after that. It did take about 2000 miles to completely smooth out and now (at 6000 miles) is just as smooth as the 6 speed in my old 2010.

Posted

These transmissions are filled at the transmission assembly plant and normally need no addition/reduction of fluid. On occassion I'm sure it's possible that the vehicle assembly plant might have a need to add/reduce fluid, but as a rule this should be uncommon. Your dealership talked about an "air bubble", there is no "air bubble". If the trans was overfilled it's possible it could create a foaming condition or if underfilled it could cause the lack of suction of fluid but both of those conditions should be extremely rare or non-existent if the oil level is set correctly. Since they removed fluid, a practice that should rarely be required, perhaps you should have them or another dealer recheck the oil level and then adjust it as necessary. It's unlikely, but possible that they removed too much and not that is further adding to you harsh shift concerns.

Yes, there is an air bubble, except it is not inside the transmission.

  • 5 months later...
Posted

 

 

900 miles on a truck that needs around 1500-2000 miles for all of the transmission adapt tables to get sorted out. My 2016 All Terrain had firm shifts and weird shifts as well, they pretty much went away by around 1500 miles or so.

 

 

I just had my torque converter replaced and they reset the TCM. So I am not at square one. when the truck was new I had downshift clunks that went away, but no hard shifting or noises. Now it slams from 1-2 and 2-3 and makes a noise that sounds like a manual tranny with b ad synchros.

 

did yours do that? and it went away after 1500 miles?

  • Like 1
Posted

I have a 2015 silverado. It has been doing that since i bought it. Now i have 40k miles and i have been to 4 different dealers in 4 different states. And every one of them said it is "normal" though i dont know officially because im not tearing apart my truck. But gm is known to have issues with the limited slip diffs. Its a largely known issue. So considering that they already put out an update for my 4x4 engaging on its own it makes it hard to tell the cause and the issue. I am under the assumption that the faulty diff has led to my giant clunking and improper shifting. Because my issue started with just mild clunking. It has evolved to my transmission slipping, the clunks now jerk my whole truck. And if the roads are wet after coming to a complete stop my truck loses all traction in the rear and i slide everywhere. I have also noticed while coming down a parking garage that the back of my truck was jumping as i circled down to the bottom floor. So i think the problem started in my rear diff. And has escalated to much more than that since the mechanics at all the dealers i have been dont seem to have any mechanical aptitude.

  • Like 1
Posted

just ran to Lowe's, chirped the tires twice slamming into 2nd while accelerating. not cool....

  • 2 years later...
Posted

I purchased a 2016 about six weeks ago. The transmission shifted hard from 2nd to 3rd most of the time and felt like it did not want to down shift alot of times. Took to a transmission shop I trust and they are upgrading the thermal bypass valve and reprogramming the TCM with a custom program. ( be aware that this will void your warranty). If I have any issues with the drive train I will have to have the TCM set back to factory before sending it to the dealer. I have also had diff issues, my tires spin all the time in the rain and at one point after the tires spun the left rear locked up. Had to stop and backup to free it up. (Sucks that I am not enjoying my new truck!)

  • 6 months later...
Posted

Has anyone had their transmission rebuilt because of this?  Mine is currently in the shop for the 3rd time and now they are saying "multiple internal failures".  They want GM to do a full replacement, GM says no - only will authorize a rebuild.  

Any thoughts on this?  Is a rebuild sufficient?  

  • 3 weeks later...
Posted

has anyone resolved this issue? because my 2016 high country is shifting hard from 1-2 going downhill and jerks going uphill. I don't want to go to a million different dealers to eventually find the solution. so if anyone has any good information please let me know what y'all did to get the problem resolved.

  • 1 month later...

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