2009 Suburban 2500 / 2009 Silverado LMM 6.6 Swap - General Info

[JMP2020]

Hey everyone,

I’m looking to drop a Duramax into my 2009 Suburban 2500 LT (currently has the 6.0L gas engine) and could really use some advice. I’ve seen a few people do LBZ or LMM swaps, but I’m not totally sure which engine/year is easiest for a 2009 chassis. Wiring and electronics seem to be the biggest hurdle, especially with the different ECM/TCM setups in the diesel trucks.I would assume my best bet would be a 2009 Silverado 2500 LT.

Main Questions:

1. What’s the best Duramax for a 2009 Suburban platform? I’m trying to keep it as “factory” as possible so it’s less of a headache with the BCM and gauges.
2. What parts absolutely need to be changed or custom-fabbed? I’m expecting mounts, crossmember, driveshaft(s), fuel system, and radiator/intercooler at minimum. But is there anything else that’s a must-do, like the front clip or a body lift?
3. For those who’ve done it, how did you handle wiring? Is there a “simple” harness merge, or am I looking at a serious re-pin job with the LMM harness?
4. Any hidden issues I might run into with the Allison 1000 fitment under the stock trans tunnel or hooking up to the stock Suburban transfer case?

I’m open to any suggestions on shops that can help with harness mods or tuning. preferably would like to do most of it myself.

Thanks in advance for any pointers. If you’ve done a similar swap—or even if you just know these trucks inside out—please let me know what you ran into. Appreciate any and all input!

Also are there any loose write ups on generally what needs to be done? Most worried about the electronics.

Trying to put a plan together to start the swap in the next couple months. BR John

 

[kidturbo]

I'm not a Duraburb master, are several of those around here. But going with a 2009 Duramax into a 2009 Suburban should be about as close to plug-N-play as you can get. Wiring and communication wise, shouldn't require much more than swapping the chassis harness where it connects into the fuse block. Everything is same GMLAN CANbus, so once VATS is relearned, chassis and engine should be happy.

All I can offer. Best of luck.

 

[2004LB7]

Might want to swap out the cluster to get the RPMs correct

 

[JMP2020]

Appreciate all the Info guys, would swapping the ignition and column with the cluster from the donor get rid of the VATS problem, or pretty easy to relearn?

 

[2004LB7]

Easy to relearn

 

[kidturbo]

Yeah no VATS issue, should fire right up.