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DURAtotheMAX
January 8th, 2015, 08:37 AM
I mentioned it briefly in another thread, but I figured I would start a new thread devoted to the new 2015.5+ TCM just to give everyone a heads up the details.

Mid-year 2015, roughly after August 2014 build date, GM/Allison made some changes to the transmission wiring harness, changed to a new TCM, and new speed sensors.

The speed sensors changed from the traditional AC 'analog' variable-reluctance type (IE, the type that has been around for 30 years) to newer DC hall-effect sensors that produce digital (square wave) signals. DC/hall-effect sensors are more accurate, less susceptible to signal noise/interference.

And from an electrical/technical standpoint, its also possible with DC sensors for the TCM's to run more advanced diagnostics on the circuit and sensor...which gives more precise information to the scan tool when there is a fault, thus making it easier for technicians to diagnose problems.

If you have a 2015 truck, look at your glovebox RPO sticker... if you see the code "AVF", that means your truck is a late-build 2015, and has the new DC speed sensors and new TCM.

The TCM on 2015.5+ trucks with "AVF" RPO code is completely different. The 2015.5/AVF trucks no longer use an Allison A40/A50/T14 controller. They now use the GM T87 controller. It looks completely different, has a different connector, and is made by Hitachi. Its the same TCM that the 8-speed 8L90 in the new Corvette and 6.2 half ton Silverados has.

So now the Corvette (w/ 8-speed auto), 2015+ half ton silverado (w/ 8-speed auto), and 2015.5+ Silverado HD (w/ Allison and AVF code) all share the same new T87 controller. Note: the T87 is NOT the same controller that the Aisin 8-speed in the new CTS uses, the T87 is Hitachi and supposedly runs all GM-in-house software.

The T87 is on parts restriction from GM (p/n 24272004), but Im sure at some point Ross will get his hands on one to let 8-speed 'Vette and 2015.5+ Allison guys play around. :mrgreen:

Ben

DURAtotheMAX
January 8th, 2015, 08:41 AM
Heres a picture of it if anyone is interested.

17912

GMPX
January 8th, 2015, 09:00 AM
Here is another picture :mrgreen:

http://download.efilive.com/Staff/GMPX/T87.png

We were lucky enough that one of our customers had an in house project on these and needed read/flash support ASAP, so we had a T87 TCM here for a few days to get that working.
Yes you are right, they cannot be ordered yet so we are very thankful we had the opportunity we did.

I have not even looked at the mapping side of them but I am concerned for sure as these run either the Allison or 8 speed ! Must be pretty universal in how it works which might mean nothing is carry over from the A50 or the T43. I think it was actually made by Continental, not Hitachi.
But this appears to be GM's new direction, outsource the hardware design and keep the software in house (yay!!)

Cheers,
Ross

GMC-2002-Dmax
January 8th, 2015, 09:12 AM
Always something cooking in that back room at EFI-Live

GMPX
January 8th, 2015, 09:16 AM
Yep, always got a million things on the go at once :Eyecrazy:

Dmaxink
January 8th, 2015, 09:36 AM
Here is another picture :mrgreen:

http://download.efilive.com/Staff/GMPX/T87.png

We were lucky enough that one of our customers had an in house project on these and needed read/flash support ASAP, so we had a T87 TCM here for a few days to get that working.
Yes you are right, they cannot be ordered yet so we are very thankful we had the opportunity we did.

I have not even looked at the mapping side of them but I am concerned for sure as these run either the Allison or 8 speed ! Must be pretty universal in how it works which might mean nothing is carry over from the A50 or the T43. I think it was actually made by Continental, not Hitachi.
But this appears to be GM's new direction, outsource the hardware design and keep the software in house (yay!!)

Cheers,
Ross

Impressive... i need some of the coffee your on!

DURAtotheMAX
January 8th, 2015, 11:18 AM
Here is another picture :mrgreen:

http://download.efilive.com/Staff/GMPX/T87.png

We were lucky enough that one of our customers had an in house project on these and needed read/flash support ASAP, so we had a T87 TCM here for a few days to get that working.
Yes you are right, they cannot be ordered yet so we are very thankful we had the opportunity we did.

I have not even looked at the mapping side of them but I am concerned for sure as these run either the Allison or 8 speed ! Must be pretty universal in how it works which might mean nothing is carry over from the A50 or the T43. I think it was actually made by Continental, not Hitachi.
But this appears to be GM's new direction, outsource the hardware design and keep the software in house (yay!!)

Cheers,
Ross

Wow!! Great work Ross!!! 4mb flash is impressive. Nice to see that GM is doing the software themselves instead of just tuning someone elses.

Chavez91
February 19th, 2015, 11:32 AM
Got some T87 DMax files, if you need some Ross :P

GMPX
February 19th, 2015, 02:55 PM
I did get a read from one sent in thanks. Really odd situation, looks like Allison are running their own code on the T87, it is not shared with the new 8 speed at all, just common hardware.
The Allison read we got was OS 24274899, if you have anything different then please Email it to support.

Thanks,
Ross

Highlander
October 21st, 2015, 03:06 AM
Do you think the E67 can talk to this transmission?

Thanks

GMPX
October 21st, 2015, 08:30 AM
Maybe, maybe not. You would need to use as late as possible OS, maybe even one from a 2015 / 2016 LSA HSV.

Dmaxink
October 27th, 2015, 03:29 PM
I did get a read from one sent in thanks. Really odd situation, looks like Allison are running their own code on the T87, it is not shared with the new 8 speed at all, just common hardware.
The Allison read we got was OS 24274899, if you have anything different then please Email it to support.

Thanks,
Ross

Did any of the strings line up with A50? I have not dug into t87 at all.

GMPX
October 27th, 2015, 07:08 PM
Mmmm, not really Kory, shoot me an Email on it.

catman3126
February 9th, 2016, 07:06 AM
Anything new on these? I own one of these and have a couple at reach I can use if some testing is needed.

Dmaxink
February 12th, 2016, 06:50 PM
Anything new on these? I own one of these and have a couple at reach I can use if some testing is needed.

I don't think so really.... Very complicated tcm. Line psi controls have really been the killer on trying to find for us.