LMM stand alone manual shift and high idle?

Mogman

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May 3, 2020
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Is it possible to set up manual shift and or high idle (for running hydraulics) in a stand alone LMM/Allison install?
I am running a ECM/TCM/TCCM but no BCM
If so where can I find this information?
THANKS!!
 

kidturbo

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Can be done a couple of different ways. The high idle control is easy with PTO module. However, the manual shift isn't without a BCM. Adding a BCM and shifting lever out of a truck would be the quickest and easiest by far.

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Mogman

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May 3, 2020
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Can be done a couple of different ways. The high idle control is easy with PTO module. However, the manual shift isn't without a BCM. Adding a BCM and shifting lever out of a truck would be the quickest and easiest by far.

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Thanks, a search does not turn anything up about a PTO module, this is in a Humvee and there is not allot of room for the BCM or anything for that matter.
I think my next conversion will be an LBZ, as I understand many more of the operations are done in the ECM because of the lack of emissions that take up memory in the ECM like cruise control, I am running an aftermarket LS cruise control that works great on the LMM.
I would assume it would take a ton of programming to get the BCM to work without all the stuff it is normally connected to?
I am not even sure I still have the BCM, I will have to look for it.
 

Mogman

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May 3, 2020
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Also I don't think it would be practical to use the shifter mounted switches.
It looks like the PTO module requires the BCM also, too bad it is not available in the Dakota Digital LS cruise control, seems like it would be easy enough.
 
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kidturbo

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I've done an Allison behind a duramax in a boat once, and without manual mode, it wasn't very happy.

I can sell ya module to do it without a BCM, but looking at $500. While ya can do it with BCM from a Dmax truck, no programming is required, for less than $50

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Mogman

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Curious, is the manual mode normally activated by the transmission being shifted down one position (as in the transmission has the "switch") or is there a switch in the column?
My subscription has expired where I get the schematics...
 

kidturbo

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Yes the shifter lever contains the switch for manual mode, along with the Up/Down buttons and Tow/Haul mode. Everything feeds to the BCM, then is send by CANbus data to the ECM and TCM. You can replace the factory lever with some simple push buttons and resistors to set each mode.

Below is a schematic for 2016 shared by another member. Don't believe anything has changes from LMM.

 
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Mogman

Member
May 3, 2020
341
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Papalote, TX
Yes the shifter lever contains the switch for manual mode, along with the Up/Down buttons and Tow/Haul mode. Everything feeds to the BCM, then is send by CANbus data to the ECM and TCM. You can replace the factory lever with some simple push buttons and resistors to set each mode.

Below is a schematic for 2016 shared by another member. Don't believe anything has changes from LMM.

Thanks, I do not see the manual shift switch only the tap up/down and tow mode switches, I might just be missing it.
The LMM must be shifted into manual out of drive that is why I was thinking the manual mode would be part of the mode switch in the transmission.
But it also looks like a tow mode switch would be easy to have with the BCM in place.
 
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