5 speed OD lock out

[LB72004]

so i have had this problem for a while. when i first got my truck several years ago i had to replace my BCM as the headlights where stuck on. i found a used one online with the same part number and everything seemed good. the only problem i have noticed is the OD lock out wont activate. tow haul works great so i know the wires are fine.

is this just a BCM programming thing? i thought that all of the 04 LB7s had the over drive lock out function programmed in them. is it possible that the some BCMs where used in Gassers and had no OD LO and this is what i happened to use? was looking forward to doing the 5 speed manual gear select upgrade and will need this function to work to do it.

anyone have any other ideas for me to check before i try another BCM or, gasp!!! go to the dealer for programming?

thanks
Jason

[THEFERMANATOR]

GM used teh sam BCM's from 03-05, only changes were in the programming. You MUST take it to a GM dealer and have them use the TIS system and flash the BCM to YOUR VIN for all of the factory installed features to work properly.

[LB72004]

thanks, that's what i thought. figured if any one knew it would be you.

so what does the VIN number in the BCM actually do? on my BCM i didn't program anything. i just did the long version of the VAT relearn with cycling the ignition. if i found a BCM that had all of the functions and did the same VAT relearn procedure or used EFI Live to do it would the OD LO work? it doesn't seem likely that this function is dependent on the VIN number if everything else works. unless there is more to this that i am not familiar with.

right now i can find BCMs for cheaper then the dealer will program mine (2-3 BCMs for one dealer reprogram). but to keep buying BCMs that wont work without the programming seems like it wont be worth it.

just want to know what direction to go next

Thanks Jason

[Big Mike]

The VIN would tell you it's from an Allison 5-speed equipped truck thus would have the programming for O/D lockout. Even if the replacement BCM is from a 2004, if it wasn't Allison equipped it won't be programmed to send the O/D lockout request to the TCM, since they're wouldn't be one there on a 4-speed auto. SO your current BCM is likely from a 4L80E equipped truck.

[THEFERMANATOR]

The VIN would tell you it's from an Allison 5-speed equipped truck thus would have the programming for O/D lockout. Even if the replacement BCM is from a 2004, if it wasn't Allison equipped it won't be programmed to send the O/D lockout request to the TCM, since they're wouldn't be one there on a 4-speed auto. SO your current BCM is likely from a 4L80E equipped truck.

What he said. teh VIN number isn't the key, but it is what features are enabled inside the BCM that is the key. And GM uses your VIn number as it lists ALL options factory installed and even lists the factory authorized installed options that have been enabled in the BCM. They enter teh VIN number into there system, and then teh correct options list is loaded in based off of teh VIN number they enter. I went on AUTOTRADER and found a base model work truck, and used that VIN number to program my BCM with to work better in my swap so it wouldn't be looking for modules that weren't present in the system and allow it to work faster as my tow/haul module(tow/haul is the only reason I have one installed in my BURB).

[LB72004]

thank you guys. that was the information that i needed.

i remember reading your thread about getting your T/H to work and dealing with the BCM. thats what made me think if any one would know you would. once again thanks Jason

[LB72004]

does $120 sound reasonable for the dealer to reprogram my BCM? they even had doubts that it was even possible to reprogram a BCM and was surprised i was able to get the engine started. dumb dealer...

anyone know of a good shop in the Sacramento area that knows what they are doing and dont charge an arm & leg for simple things. $120 seems like a bit much to enable the OD LO, i guess it all depends of how badly i need it.

Thanks Jason

[rcr1978]

I think all dealers charge a 1hr min for any module flashing or just a flat rate like the one you got.

[THEFERMANATOR]

Yep, most charge a 1 hour minumum even though I know it only takes them 15 minutes to flash a BCM including scratching there A$$ during the process. I think it took him less than 5 minutes to do my BCM.

[LB72004]

so no honest shops in the Sacramento area that can do this?

15 minutes to flash a BCM, that means they are making over $450 an hour! i think i will take my chances on a used BCM. do you think my best chance is a BCM from an 05 duramax, to make sure it has the latest calibration from GM?