T87A Bins to Pins - Who's In ?

[Tre-Cool]

interesting info. I was wondering how i'd go with using a t87a in place of a t93 since that is what i pulled out of the car i got my 10l90's from.

Hopefully the solenoid info on the sticker is not restricted to the original ecu type.

Likely works if wired up correctly, and I remain undecided..

Spent last couple months attempting to sort those exact questions on T87A stand-alone frankenstein build. And the past 48 hours confirming most of them.. lol

Pinout matters, and can likely use your factory T93 by time you have it all bolted together.

the t93 looks pretty crusty and burnt so im not even sure it's a goer.

I'll happily send some cash your way for a couple of units along with the solenoid stickers to get programmed right.

[usbbdm]

This is usbbdm, I do not go this site very often since I am busy. The so called unlock of T87a (dll 0.01) does not do much, it simply modified a few bytes that mimic the way HPT to bypass the SHA check when programing. I have found a better way to unlock T87A which allows the custom kernel to be downloaded similar to T87.
I will soon release this kernel so you can use regular CAN BUS (not GM boot mode), load custom kernel to do real read/write at full speed. Yes read/write at 30KB/s speed as with E39A. I will see if this unlock method works for newer ECUs((TCUs). I think HTP needs to use this new method to do the programing.

[kidturbo]

This is usbbdm, I do not go this site very often since I am busy. The so called unlock of T87a (dll 0.01) does not do much, it simply modified a few bytes that mimic the way HPT to bypass the SHA check when programing. I have found a better way to unlock T87A which allows the custom kernel to be downloaded similar to T87.
I will soon release this kernel so you can use regular CAN BUS (not GM boot mode), load custom kernel to do real read/write at full speed. Yes read/write at 30KB/s speed as with E39A. I will see if this unlock method works for newer ECUs((TCUs). I think HTP needs to use this new method to do the programing.

Now that sounds like some encouraging news.

Thanks for all the hard work sorting out this STI chip. I was just comparing the boot segments between the T87 and T87A on the Allison 6spd units a few days ago. Noticed those sections are completely different between hardware, while other segments are more similar in layout. My first thought was, could we segment swap those to accomplish an unlocked T87A.

The GM Diesel trucks from 17-19 came equipped with Allison 1000 transmission. Early models with T87, while later used the T87A. Both are exact same 6spd transmission going back to 2006. However, Allison modified the tail shaft in 2017+ to accept a new style current driven square wave speed sensors. Electronically the same as our 8spd and 10spd gasser units. But the Allison only has 2 speed sensors, Turbine & Output Shafts. And I don't believe either reads or cares about direction like our 10spds. Both units OS also share the same 6 pin range switch as earlier.

Reason I share, this platform is only one I've found that used both the T87 and T87A, where TCM hardware is interchangeable. You can swap out your T87 for T87A in same truck and all good. Meaning besides the boots, all other parts of our bins are basically identical. Plus the primary T87A A2l floating out there is for the Allison 6spd, and in the header, it denotes the code base going back to 2014. Internally there is some obvious hardware upgrades in the T87A, but mostly small parts like resistors and circuit isolation pieces. Betting the main MPU pinout never changed..

[MPC001]

way to go with U-Link NT

This is usbbdm, I do not go this site very often since I am busy. The so called unlock of T87a (dll 0.01) does not do much, it simply modified a few bytes that mimic the way HPT to bypass the SHA check when programing. I have found a better way to unlock T87A which allows the custom kernel to be downloaded similar to T87.
I will soon release this kernel so you can use regular CAN BUS (not GM boot mode), load custom kernel to do real read/write at full speed. Yes read/write at 30KB/s speed as with E39A. I will see if this unlock method works for newer ECUs((TCUs). I think HTP needs to use this new method to do the programing.

[kidturbo]

the t93 looks pretty crusty and burnt so im not even sure it's a goer.

I'll happily send some cash your way for a couple of units along with the solenoid stickers to get programmed right.

Just so happened to bring one home for bench testing that came on the 2020 Gen2 unit I was playing with over the weekend.

While trying to sort out the exact differences between Gen_ valve bodies and our TCM pinouts, I slapped that stock T93 back in place of the T87A and fired up the car. Was amazed, it acted like fairly happy receiving the same Emulated GMLAN data that makes the T87A happy. And since I was capturing raw canbus at the time, got a few bytes to examine. The valve body and PUN I'm using isn't same as that TCM came with..

After speaking with others way more familiar with these style swaps, I don't believe it's a huge stickler to Not load the matching PUN. Am told it's basically the factory way of making them shift smooth and perfect straight off assembly line, vs having to do a relearn. Sounds reasonable enough to me. But after first test drive with Gen2 valve body controlled by T87A, reviewed the data and didn't like the flaring noted on each upshift. We caught trans temps rising quickly up over 200F range, so parked the car and called it a day..

I received a msg today from the owner that he found the shifter cable was out of calibration when he moved the car today. Actually jumped out of gear from D to N. He adjusted the cable, took car on a drive. Couple soft launches, and said drove like totally different car compared to our test drive on Saturday. No data to compare, but if the clutches are still good from Saturday, then I'm going with that main control valve out of specs being cause of the slip noted and not related to PUN mismatch.

As for the differences between Gen1 and Gen2 bodies, the latter has an extra solenoid in there we need to account for. If someone can dig up a Gen2 T93 schematic, happy to point out that little sucker in the pinout, and what to do. If that solenoid is Not powered correctly, IE by a T87A, it will cause some serious head scratching from all those standing around.. Reverse is now Forward, and Forward is a Trans Brake, locking the rear wheels, and holds pretty good I must say.. LOL

Being this test bed is frankenstien build, we had to sort some other hardware issues early on that caused very weird results. So when I saw the wheels spinning forward in reverse, my first thoughts went back to hardware. However when disconnected the TCM from the harness, fired up the engine, now reverse was reverse and drive was now forward again.. Head scratching stopped when I popped in the T93, and transmission responded correctly when shifted. Verified it was wiring related, and the difference between Gen1 and Gen2. We also had correct Gen1 valve body on hand, but decided to sort it electronically rather than just swap hardware. One wire makes all the difference...

[usbbdm]

I just uploaded 1.76.
The new DLL for T87A (0.02) add calculate the checksum for boot block. If you have your own way of unlock you can use this to generate legit boot block.
The unlock add feature that allow you to load your own kernel in addition of existing bypass sha check used by HTP.
Target of TCUT87ACAN target created and it gets read speed of 32-33KB/s (GM boot mode can only get 8-9KB/s) and write speed (exclude boot block) at 29KB/s.
If HPT decide they can use their own kernel to program the device (same as T87). No special wire needed. When read this is true read of the flash. Shadow memory can also be read.

[gmtech825]

If you need an xdf for a certain OS let me know, I'll see what I can do

[usbbdm]

https://youtu.be/cHNuKVS041Q
Video created for new T87A with custom kernel.

[kidturbo]

https://youtu.be/cHNuKVS041Q
Video created for new T87A with custom kernel.

Looking good.
Will give it a try shortly.
Jtag, boot mode, unlock, a custom kernal for J2534 mode with first ever read out options.. Not to shabby for couple months of work.

Do you have a T93 to play with yet?

[usbbdm]

Yes I have one. Need first make JTAG working.