Allison TCM Reprogram Issue

[Mike O.]

After seeing the post regarding the new Allison TCM software update here (GM TechLink July 2002, Vol 4, No 6)I took my '01 2500HD in for the fix.

However, I think they installed the OLD PCM fix that has been around since Oct. 2001, (Calibration No. 15097103) so I need more information to fight my case.

What is the Calibration No. for the NEW TCM upgrade, anyone know?

What is the URL address for the GM website to check for new calibration updates - I missplaced it?

[BLUMAX]

I think this is the site you're wanting ...
http://vci.ecomm.gm.com/vci/
Where you enter your VIN # and check for calibration info, hope it helps smile.gif

[Buckman]

Mike O. : Be sure that your dealer updates BOTH the TCM and PCM. On the MY2001, it is important that both the transmission and the engine have the most recent updates to realize all the calibration enhancements for overall engine/transmission performance.

And that's all I have to say!!! :D :D

[Mike O.]

Blu Max and Buckman,
Thanks, that's the info I needed. As it turned out the dealer had only done the PCM. When I showed them the printed pg. 6 from the July GM TechLink they upgraded the TCM as well. Jeez! You really have to watch these people.

[Captain Mal]

Mike,

What did the upgrade do to your shifting and towing?

I want to have it done but can't find out if it's worth it. My dealer wants $80 to do the re-flash on my '01 like yours.

Is it worth it?

'01 GMC 2500 D/A ext sb 4x4

[SoMnDMAX]

Captain, the reflash works quite well. On my '01, the improvement in the shifting was immediately noticeable, and a definite step in the right direction. The 1-2 and the 2-1 shifts are smoother and "complete", I had an issue with the 3-4 shift from time to time, and that's fixed. The tranny shifting patterns are much more fine tuned, and more user friendly. I'd go for it.

$80 is too much to be charged for something that only takes a half hour max.... I'd check a couple of other dealers.

[Captain Mal]

SoMnDmax,

Thanks for the response and information. I'm kinda surprised about the shifting you spoke of as I never even had a hint that those lower gear shifts were an issue to anyone. All my complaints are related to the 4 to 5 upshifts and downshifts while towing. That's all I ever read about from anyone else.

Thanks for the info again but it was quite a surprise to hear your comments. Still don't know what the flash does to the 4 to 5 towing 'business' problem that is so obnoxious and widespread.

This is my first automatic transmission in over 40 years of driving. What a pain this Allison is and I hear it's a good model. Sometimes the old ways are the best ways.

'01 GMC 2500 D/A ext sb 4x4

[Robert McClelland]

For Blue Max
The URL for the Trans update by Vin # did not work. My 2001 GMC built in Jan 01 has never been back to the dealer. I called the dealer about TCM & PCM updates and they would not tell me anything. I have 17k on it and I love it.

[mdrag]

Robert McClelland,

When you said the link did not work, what did you mean? I cut and pasted the above link http://vci.ecomm.gm.com/vci/ and the GM calibration website came up.

FWIW, the GM calibration site DOES NOT list the updates for the TCM, only the updates for the PCM/ECM/VCM.

Here's my version of how the GM Calibration site works from a previous post:

http://forum.62-65-dieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=7&t=003312&p=


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The GM Calibration site:

http://vci.ecomm.gm.com/vci/

This site lists ALL the AVAILABLE ECM/PCM software and updates for your vehicle, not the software that is installed. When new software is available, it will be added to the bottom of each section. The listing will not change after you have an update(s) performed - it will only change when new software is released.

The only way I know to check the INSTALLED SOFTWARE in your truck is to use a TECH2 to download the software versions from your vehicle and check it against the list. This is what the dealer has to do.

I printed out the page when my truck was en route from the factory and, and when I checked and saw that something was new on the list - I went to the dealer with my list of 'complaints' and had the new software installed (after reading positive posts on the new versions).

AFAIK, no one has found a website for the TCM programming - the GM site is ONLY for the ECM/PCM.

See this post for more info:

http://forum.62-65-dieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=7&t=003046&p=

This is my version of how the GM Calibration site works - I reserve the right to change my mind in the future. ;) :D

[Robert McClelland]

Thanks MDRAG
I got the web site. My next step will be to take it in to the dealer and talk about my down shifing . I will also ask them to check all the vehicle calibration program updates.