T87 Swaps

[kidturbo]

I agree that a used $50 unit should perform just as well as a brand new. These are a very robust little box.

What ya might need from GM dealer is the 2 speed sensors for a 2016 transmission. We've yet to source those part #'s.

I'm working on a ACME Adapter Kit for those, but requires more testing.

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[pl_silverado]

Honestly, I wouldn't bother with a brand new one. Look to car-part.com and there are plenty... 36 pages of them. At the high end, they're insane (2,899, 2,000!?!?!?!?), and a lot are out of touch... Considering you can buy a NEW one from one of the many GM Parts stores online for $175ish, Anything over $100 used, IMO, is nuts, but if you sort by price, there are a bunch that I'd consider 'reasonable' after page 25/26 (at time of posting LOL).

Honestly it’s just not worth the time to save $40-50. Hell, Amazon has them for $145. The amount of money I’ve spent on new T14’s / A50’s in comparison this year makes the t87’s seem like a joke price wise.

 

[pl_silverado]

I agree that a used $50 unit should perform just as well as a brand new. These are a very robust little box.

What ya might need from GM dealer is the 2 speed sensors for a 2016 transmission. We've yet to source those part #'s.

I'm working on a ACME Adapter Kit for those, but requires more testing.

Sent from my SM-S901U using Tapatalk

I’ll find those part numbers today and post them.

 

[pl_silverado]

here you go guys.

 

[pl_silverado]

Service connector part numbers, if they are different at all, i did not have time to compare to lmm or early lml versions.

 

[2004LB7]

Now watch the price suddenly jump up

 

[pl_silverado]

Now watch the price suddenly jump up

Wouldn't surprise me at all. I grabbed a new one off amazon for $145, and they had a used one in warehouse deals for $45, grabbed that too. We'll see.

 

[pl_silverado]

L5P Mount Part Number

 

[kidturbo]

That pretty much wraps up the hards parts list. Thanks for the numbers and diagrams @pl_silverado.

For shits and giggles, what's mounted in that firewall location on A40 A50 trucks?? I recall something blocking that area.

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[kidturbo]

Now watch the price suddenly jump up

There are plenty of 4 bangers and six cylinders out there in the bone yards, nobody will likely lift a hood on..
@Cougar281 and I have mastered a little EFI hack that makes those models just as valuable to this swap as one from a 16 Dmax truck. Finally, a reason to rejoice that TCM tuning is now FREE!! For the past decade, I've had a couple dozen unused TCM licenses.. Doing only boats, I kept feeling I was wasting money not using those..



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[pl_silverado]

That pretty much wraps up the hards parts list. Thanks for the numbers and diagrams @pl_silverado.

For shits and giggles, what's mounted in that firewall location on A40 A50 trucks?? I recall something blocking that area.

Sent from my SM-S901U using Tapatalk

nothing on the lmms. There’s a nox sensor on the LML’s if I remember correctly, so the studs on those might even line up.

 

[kidturbo]

nothing on the lmms. There’s a nox sensor on the LML’s if I remember correctly.

Interesting... I was thinking the booster assembly blocked it. Well if the T87 doesn't like the radiator for any reason, can always extend the cable and go where GM went.

 

[Cougar281]

Interesting... I was thinking the booster assembly blocked it. Well if the T87 doesn't like the radiator for any reason, can always extend the cable and go where GM went.

Considering the TCM harness comes from/through the fuse box, might not even need to extend it, just reroute it.

 

[pl_silverado]

Interesting... I was thinking the booster assembly blocked it. Well if the T87 doesn't like the radiator for any reason, can always extend the cable and go where GM went.

This trucks more complete

I have 3 relays mounted there but it looks like there’s plenty of room.

 

[pl_silverado]

Considering the TCM harness comes from/through the fuse box, might not even need to extend it, just reroute it.

I’ll play with the wiring and mounting location on one of the trucks and come up with something as soon as all the parts show up.

 

[kidturbo]

Fender Brace... I knew something was different. Ya guys will have to forgive my ignorance, since I'm probably the only member on here who's never owned a Duramax truck.. Wrenched on a few, but usually that's robbing parts for something they never belonged in....

 

[pl_silverado]

I don’t think the brace will interfere with anything aside from maybe it being easier to install it with it out of the way. 2 minutes to take it off so not much of a concern.

 

[kidturbo]

Did a little more bench work last night, and was able to satisfy all the missing Comms DTC errors. Running LMM ECM along with my crank/cam emulator, and a CANbus gateway substituting the missing data parameters. Similar to the E38 approach, but with actually less data required on this Allison OS setup. Then I just spoofed it with some data packets recorded from a buddies L5P truck, and it instantly cleared the missing BCM and EBCM codes. Now to get a valve body connected..

Also need to load my stand alone LMM boat tune so it clears this GPCM code and a few others. Then we should have 2 Happy Bench Campers..

 

[Cougar281]

Did a little more bench work last night, and was able to satisfy all the missing Comms DTC errors. Running LMM ECM along with my crank/cam emulator, and a CANbus gateway substituting the missing data parameters. Similar to the E38 approach, but with actually less data required on this Allison OS setup. Then I just spoofed it with some data packets recorded from a buddies L5P truck, and it instantly cleared the missing BCM and EBCM codes. Now to get a valve body connected..

Also need to load my stand alone LMM boat tune so it clears this GPCM code and a few others. Then we should have 2 Happy Bench Campers..



View attachment 120144

Being as how the 2007+ GMT900's have HS GMLAN going to both the BCM and EBCM, the BCM and EBCM codes MIGHT not be an issue... Without having an appropriate BCM and EBCM on the bench to futz with, I can't say (I do have a 2015 BCM that makes the TCM happy, but I don't have a 2007-2014 BCM, which is a different animal, which may or may not make the TCM happy)... The couple of missing parameters that trigger the P0100 may be the main hurdle with 2007+ GM900 trucks (as Ken and I have discussed, feeding the same parameters with a E35A LBZ ECM also makes the T87 happy). As mentioned before, the red-headed stepchild LBZ would be the challenge, because they were kind of a crossover... They moved from the J1939 that was used for ECM-TCM-GPCM comms to GMLAN, but they still used Class2 for 'less critical' things like the PRNDL display in the IPC, Tow/Haul, etc. I suspect that in a LBZ, with what we've found and how to get around it, the TCM would likely function ok, but we'd be missing those other bits... unless there happens to be a Class2 transceiver on a pin somewhere. Not holding my breath on that one though lol.

 

[kidturbo]

A couple things I do notice missing from our 35B ECM traffic, are packets that carry Transfer Case / Driver Mode Switches [IE:TowHaul] and from our LMM years BCM is Tap Shift Data.

Someone please refresh my memory on how Tap Shift was handled back then. TowHaul is actually in a ECM packet, so the BCM passes that button off to our ECM, to then tell the TCM what it wants. But I recall something different about Tap Shift on the early GMLAN stuff.