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Scott W
Scott W, Technician
Category: Transmissions
Satisfied Customers: 3312
Experience:  I am trained Ford transmission tech, and have 28 years in the field.
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I am working on a friends 2011 GMC Sierra Denali 2500HD with

Customer Question

I am working on a friends 2011 GMC Sierra Denali 2500HD with the 6.6 duramax and allison transmission. We live in remote Alaska so unable to get to dealer easily. He has had major issues with his transmission (getting locked out, stuck in gear, slamming shifts etc.) We had it at the dealer and they said they couldn't figure it out and to replace the ecm. So I have purchased an acdelco ECM as well as an acdelco tcm. I have also purchased a tech2 and have some questions regarding the procedure to flash those modules, I understand I will need to pay for the short term pass to tis2web. I believe I am missing the cord that goes from tech2 to PC for updating and downloading, any info on which cord that is would be great.
Submitted: 11 months ago.
Category: Transmissions
Customer: replied 11 months ago.
I really just need some guidance weather or not I need to pull any info off the existing ECM and TCM before flashing the new units.
Expert:  Joe Prestia replied 11 months ago.

The cable you're asking about for this operation is the j-2534 cable which allows for bi-directional communication. As long as you install the updates provided to you from tis2web in your temporary subscription you'll be good to go! All this of course, assuming that the dealer you took it to pointed you in the right direction. I would double check for intake leaks before I went any further. Good luck! Hope tis helps (terrible pun intended)! Let me know if there is anything else I can do!

Customer: replied 11 months ago.
what im wondering is once i download the info for the ecm and tcm from tis to the tech 2, am i able to just swap out both modules and flash them or do I need to gather any info from the vehicle before removing originals? Reason I ask is because the dealer said something about having to pull the injector numbers off of the glow plug controller, you know anything about that?
Customer: replied 11 months ago.
Looking for a little more in depth info for the tech 2 and how to flash the modules, I appreciate the time you took to respond
Expert:  Joe Prestia replied 11 months ago.

I've never heard of this before but I'm primarily a gasser guy. If that Is what they advised you to do then I would err on the side of caution and access the glow plug module with your tech II and record any information that is available to you just in case you'll need to re-input this later. Typically though you'll get all of the information you need in the software package from t2w. If this isn't what you were after please let me know so I can opt out and another tech may have chime in with what you're looking for!

Customer: replied 11 months ago.
Would be great to get another opinion, do appreciate the time you took, I want to make sure I don't brick my buddies new ecu and tcm lol so just erring on the side of caution.
Expert:  Joe Prestia replied 11 months ago.

Fair enough. For what it's worth I'll say it's pretty awesome that you're attempting this on your own in Alaska. I'm kind of impressed (and sorry that you have to deal with this bull!. They sure don't make them like they used to.). I'll opt out and we can see what anyone else may have to say!

Expert:  Joe Prestia replied 11 months ago.

No need to respond or it will revert your question back to my inbox! I'll be able to follow along just the same! Good luck!!!

Expert:  Scott W replied 11 months ago.

If you have any more questions just ask, thanks Scott

Customer: replied 11 months ago.
Scott, I am needing to flash a new ecm and tcm for the above mentioned duramax, do I need to pull anything off the old modules or am I able to download the new programming for the ecm and tcm off of tis2web and flash the modules?
Expert:  Scott W replied 11 months ago.

I am sorry, not sure how I locked onto this GM question, sorry I am a Ford tech. I will opt out.