"Allison" 10 speed hard upshift gears 7-8

[MORSNO]

17 hours ago, UWSkier said:

Finally got into a dealership to have the shift relearn done and it's back to shifting smoothly.  It took 11k miles before it started acting up before.  Hope it's good for at least a few thousand miles of towing before it hits again.  Really sucks not having 8th gear on a cross country tow.

 

Keep us posted on your results please.

[Another JR]

10 minutes ago, MORSNO said:

 

Keep us posted on your results please.

Is “relearn” really just a “control-alt-delete” by disconnecting the power long enough for memory to clear, or was it a load of a new software version?  If it was just a reset, we should be able to just do it ourselves. I know on earlier vehicles I could do this to correct certain bad shifting characteristics that had developed over time. 

[newdude]

22 minutes ago, Another JR said:

Is “relearn” really just a “control-alt-delete” by disconnecting the power long enough for memory to clear, or was it a load of a new software version?  If it was just a reset, we should be able to just do it ourselves. I know on earlier vehicles I could do this to correct certain bad shifting characteristics that had developed over time. 

 

 

Requires GM's diagnostics software GDS2. 

 

It "might" be possible to access with a higher end scan tool but I've seen issues even with up to date current Snap On scanners not being able to perform functions on GM vehicles with GM Global B architecture, like the 2024+up HDs for example.   

 

The Service Fast Learn or the Transmission Adaptive Pressure Reset for this 7-8 shift is only a temporary solution as GM is still investigating what exactly is going on.  

Edited July 27, 2024 by newdude

[UWSkier]

10 hours ago, newdude said:

 

 

Requires GM's diagnostics software GDS2. 

 

It "might" be possible to access with a higher end scan tool but I've seen issues even with up to date current Snap On scanners not being able to perform functions on GM vehicles with GM Global B architecture, like the 2024+up HDs for example.   

 

The Service Fast Learn or the Transmission Adaptive Pressure Reset for this 7-8 shift is only a temporary solution as GM is still investigating what exactly is going on.  

Yeah, I know it's only a temporary fix, but since it was fine for a year, I'm hoping it's fine for another year after having this done.  At least I hope it's fine for my camper tow from WI back to AZ next week, as it was lame going cross country without being to use 8th gear.  I also wanted it done so there's a service record of my truck having the issue so I can hopefully get faster service once the fix is released.  Crazy they've been working on this for months with no update though.  Seems pretty obvious there's a software issue.  Not sure if they have an ability to flash a firmware update but it'd seem that's the fix since it's clearly nothing mechanically wrong.

[UWSkier]

1000 miles into the tow after the relearn and 8th gear shift is working flawlessly.  Great to have it back as it's where the truck is happiest towing the camper.

[MORSNO]

22 hours ago, UWSkier said:

1000 miles into the tow after the relearn and 8th gear shift is working flawlessly.  Great to have it back as it's where the truck is happiest towing the camper.

 

Good to hear!

[UWSkier]

I've now driven about 3000 miles since having the fast learn and pressure reset done, almost all towing, and haven't had a rough shift since.

[UWSkier]

Update: still no harsh upshifts.  Likely taking another cross-country trek with the travel trailer soon.  Hope that harsh upshift doesn't return.

 

PIP5971 is the bulletin for this.  But I can't find any updates since March of 2024.  @newdude how do I go about finding out if there are any updates?

[UWSkier]

Update: IT'S BACK!

 

This will be my last GM. It has the ride quality and gas mileage of a 1938 Panzer and about as many rattles too. 

[Chuck FB]

11 hours ago, UWSkier said:

Update: IT'S BACK!

 

This will be my last GM. It has the ride quality and gas mileage of a 1938 Panzer and about as many rattles too. 

I wonder if there is more to it than software, if its a combination of both the computer control factor and a valve body issue. Back to the dealer of course and can see if there is a different course of action now given its almost a year later from the first dealer visit. When I had talked to a local transmission shop on the topic of these transmissions, because most of the issues end up back at the dealership he has not had the opportunity to work on one or even touch a valve body because a new valve body would be impossible to get ones hands on other than a dealership. I had mentioned NextGen Drivetrain to see what his response was and he didn't know much about them but certainly questioned the whole concept of orings on spool valves, but did mention that in his world of rebuilding transmissions that two companies stand out that have developed a lot of transmission fixes over the years, TransGo and Sonnax and would have faith in what they develop. I see both of those companies have a few little items they have come out with and its a few parts for the valve body and one of those items looks to be involved with preventing the transmission from trying to go into more than one gear ( the rear end momentary lock up issue ). I am purely speculating but I just wonder if your transmission is trying to pull that stunt and why the slam shift feel. I don't recall when they said that software update came along that is supposed to be warning the driver that something is starting to go wrong with the transmission,  yes I know its completely retarded but wondered if your trans electronics had that warning software update. 

 

Different truck and trans but a friend just had his 2023 1/2 ton with its 10 speed decide to go stupid and was dropping out of forward or reverse out of the blue on his way to work the other day and had it towed off to the dealer and they diagnosed it as the valve body, now its wait for who knows how long before they get the part to throw on it as there was already someone ahead of him that has been waiting almost 2 months for the very same thing on his 1/2 ton. But I bet if one goes to the Ford or Ram dealer your going to find pissed off customers, oh and add Toyota to that list. 

[fishnitro]

48 minutes ago, Chuck FB said:

I wonder if there is more to it than software, if its a combination of both the computer control factor and a valve body issue. Back to the dealer of course and can see if there is a different course of action now given its almost a year later from the first dealer visit. When I had talked to a local transmission shop on the topic of these transmissions, because most of the issues end up back at the dealership he has not had the opportunity to work on one or even touch a valve body because a new valve body would be impossible to get ones hands on other than a dealership. I had mentioned NextGen Drivetrain to see what his response was and he didn't know much about them but certainly questioned the whole concept of orings on spool valves, but did mention that in his world of rebuilding transmissions that two companies stand out that have developed a lot of transmission fixes over the years, TransGo and Sonnax and would have faith in what they develop. I see both of those companies have a few little items they have come out with and its a few parts for the valve body and one of those items looks to be involved with preventing the transmission from trying to go into more than one gear ( the rear end momentary lock up issue ). I am purely speculating but I just wonder if your transmission is trying to pull that stunt and why the slam shift feel. I don't recall when they said that software update came along that is supposed to be warning the driver that something is starting to go wrong with the transmission,  yes I know its completely retarded but wondered if your trans electronics had that warning software update. 

 

Different truck and trans but a friend just had his 2023 1/2 ton with its 10 speed decide to go stupid and was dropping out of forward or reverse out of the blue on his way to work the other day and had it towed off to the dealer and they diagnosed it as the valve body, now its wait for who knows how long before they get the part to throw on it as there was already someone ahead of him that has been waiting almost 2 months for the very same thing on his 1/2 ton. But I bet if one goes to the Ford or Ram dealer your going to find pissed off customers, oh and add Toyota to that list. 

 

I bet its something in the valve body too. I have a 24 3500 duramax and before my valve body failed with the dreaded wheel lockup deal it was shifting hard from 7th to 8th, both loaded and unloaded on just about every shift. I waited two months and got a new VB and everything felt great for a while. Now its back to being wonky with occasional harsh shifts from 7-8. I now have the parts kit from Nextgen in my hands and it will be installed next week by my mechanic who is a long term GM only guy with lots of GM transmission experience( he rebuilds them in his shop). He is familiar with Nextgen and thinks its a solid product. 

 

I too am done with GM after this latest engineering debacle. 

[Chuck FB]

57 minutes ago, fishnitro said:

 

I bet its something in the valve body too. I have a 24 3500 duramax and before my valve body failed with the dreaded wheel lockup deal it was shifting hard from 7th to 8th, both loaded and unloaded on just about every shift. I waited two months and got a new VB and everything felt great for a while. Now its back to being wonky with occasional harsh shifts from 7-8. I now have the parts kit from Nextgen in my hands and it will be installed next week by my mechanic who is a long term GM only guy with lots of GM transmission experience( he rebuilds them in his shop). He is familiar with Nextgen and thinks its a solid product. 

 

I too am done with GM after this latest engineering debacle. 

Does your truck qualify for warranty yet, although I realize even if it does that means waiting and waiting for yet another valve body that more than likely still has the same built in failure issues ... all extremely frustrating. The reason this transmission shop I talked to in person had a question mark when it came to the Nextgen kit or method as it were, is orings on a moving part such as these spools. Wear on the orings etc was his worry because for the most part he claimed that orings in a transmission are on stationary items that seal the oil from escape rather than cycled/moving parts. That's one persons opinion and its not like he has even had a kit in his hands nor installed one. The proof will be in its use, will it cure the issue and cure it for a long time. If I was in your position I'd be very tempted to do as you plan also, there is no real good answer when it comes to dealing with issues like this as it makes one feel like your beating on a dead horse to keep it moving. Keep us posted as to how it goes, what your mechanic thinks of the kit and how it seems once your able to try it. I imagine he will cut open the filter to make sure things have not gone sideways in the trans and take a read on what is on the magnetic pads. 

 

 

[newdude]

 

On 6/17/2025 at 6:24 PM, UWSkier said:

Update: still no harsh upshifts.  Likely taking another cross-country trek with the travel trailer soon.  Hope that harsh upshift doesn't return.

 

PIP5971 is the bulletin for this.  But I can't find any updates since March of 2024.  @newdude how do I go about finding out if there are any updates?

 

 

 

Just read back and saw this.  They did update it to reprogram the TCM.  It is now a bulletin and not a PI either.

 

New # is 24-NA-211.  Bulletin can be read HERE - MC-11010466-0001.pdf

 

  

 

 

Edited July 1, 2025 by newdude

[UWSkier]

6 hours ago, newdude said:

 

 

 

 

Just read back and saw this.  They did update it to reprogram the TCM.  It is now a bulleting and not a PI either.

 

New # is 24-NA-211.  Bulletin can be read HERE - MC-11010466-0001.pdf

 

  

 

 

Thank you!  Back to the dealer tomorrow for this.