LMM: Good or Bad?

[ghostrider01]

Ive found a 2007.5 LMM for sale and im just wondering if there is anything really difficult with this motor such as tunning wise or overheating or just anything in general? Ive had a LB7 and a LLY and i have heard the LB7 is peoples favorite and the LLY's overheat until you solve that over heating problem, so im just really curious what are some pro's and con's with this year and the LMM. Ive been looking around on some of the threads but havent really seen any people having any trouble with them. Ive seen some people still running thier stock tranny's and able to be in the 12's, so does that mean that the 6 speeds are pretty tough? Ill probably be using this truck for DD and drag racing and kinda interested in sled pulling also.

 

[TeaBagger2006]

just the added emmisions crap (dpf)which im sure you will get rid of. after that it basically turns into a lbz. i think the lmm have defueling issue on the 2-3 shift. you got an updated transfer case(no pump rub). the 6speed trans with a transgo jr is a very good cheap band aid for small hp increases. good tuning will get you far plus you now have the dsp switch available. i think what people dont like about these engines are the pistons.

 

[cdbright]

yea the expensive parts

 

[duramaximizer]

General tuning complications and the pistons are known to be weak as are the LBZ's. Everything else is good. :cool2:

 

[JMK777]

Yes people are geting them in to the 12s with a stock trans but that does not mean the trans will holde much longer with out limping. pistons would be my consern.

 

[ghostrider01]

So it looks like the pistons are the weak link on the LMM so far. Something else im concerned about is the dpf has been deleted and now has a Magnaflow exhuast on it but what happens if something would happen to the truck that could be covered by the factory warranty but since it dont have to dpf anymore what would i do? Because since the dpf is deleted the factory wont work on it correct? Where can i take it? Could i take it to a GM dealer and say that i have a 60 month 100,000 mile warranty, would they replace stuff for me then or would i just be crap out of luck?

 

[JMDuramaxLB7]

Alot of warranty work depends on your dealer, some don't have a problem with mods but alot of them do and G.M. is cracking down on it also.

 

[unfinished business]

I went 12.80's on a stock trans with 20" rims. So far I have been very happy with my LMM (knocking on wood)

 

[ghostrider01]

yeah i like the look of it and all i am just mainly worried with the warranty. Could i just buy a dpf for some one and put it on when i have to take it in? Is efi detectable when you set you ecm back to stock? Im wondering if i would be better off getting a different ecm and putting a tune on that on and just switch them out. This truck has 305/55/20 tires, but im already aware ill have to build the tranny because it wont last forever without limping