LBZ to 2011 GMC 2500 swap

J58Bear

New member
Sep 9, 2018
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Hey guys, first off I'm new to the forum from KC. But here's my situation. I currently own a 2011 GMC 2500 with a 6.0 Vortec/4L80E trans. My buddy just swiped a girthy mailbox and basically totaled his 2006 LBZ (it tweaked the cab) so I would like to buy his truck from him for insurance buy-back price and swap his LBZ motor and Allison into my 2011. My question is since the motor/trans and the truck model are 5 years apart, can these standalone harness outfits make me a harness that will make everything work and not have random qwerks? I.e. Have to delete the A/C or something like that. I know all the mechanical things could be swapped but I just really want to be sure about wiring and electrical before I spend money and get into something like this. Thanks in advance.
 

LCAC_Man

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Aug 27, 2017
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You would have to run an LMM ECM/TCM to get to a system that supports GMLOWSPEED data vs the Class2 Data that the LBZ ECM/TCM work on. Probably a few other wires to be moved around. You'd never be able to register/sell it in a market that has any kind of emissions inspections.
 

LCAC_Man

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Aug 27, 2017
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So they can make a harness with altered pins if I get a LMM ECM/TCM?
There's a lot of "it depends" that play into this.

Are you doing EGR delete?
If so all you would have to do is get an LMM MAF and connector and modify the LBZ harness. From what I understand the LBZ will run fine with the LMM ecm if you make the MAF change and turn off both the EGR and DPF functions in the LMM ECM.

So basically a stock LMM ECM TCM and a stock LBZ harness (egr disconnected) with an LMM MAF connector spliced on will do the trick.
Stand alone harnesses won't help you, you would loose your IPC, climate controls and tow/haul mode, you have to run an ECM/TCM combo that works on GMLOWSPEED data for all that to work.
 
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J58Bear

New member
Sep 9, 2018
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Okay thanks! And yes the LBZ motor in the truck I'm buying already has EGR fully deleted so should eliminate that portion of the swap.
 

LCAC_Man

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Aug 27, 2017
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You'll still have to have EGR and DPF turned off in the LMM ECM but there's lots of tuners out there that can do it for you.