Are LMM's really that much more reliable than the LML?
The LMM doesn't have the DEF, SCR and related sensors. But still has the DPF and CAT. Uses post injection to heat the DPF for regeneration which can wash down the cylinders and hurts power while in regen. LML uses a 9th injector to provide the heat needed for regen so seamless while driving. LML had the CP4 which has been known to fail at higher rates then the CP3 that is in the LMM.
I guess one could argue, especially with the DEF setup and CP4, that the LMM is more reliable. But I'd argue that we pretty much have all those things figured out and know how to deal with them now. With that being said. I have an LMM
In my opinion/experience, yes they are more reliable. Unfortunately I'm well ver$ed in all of the generations of duramax motors and their equipment with all the repairs and rebuilds over the years.
All 3 of my lml's were crap. One was plagued with emissions issues, solved that and then promptly lifted the heads. Then the turbo went. Second one no one could get the tunes right. Literally no one, and obviously every tune is locked down so you can't try to fiddle with it yourself to figure it out. This resulted in Reduced Engine Power Mode while towing on a regular basis.
I wouldn't buy another one. So far that's the only generation that's actually left me stranded. I'd like my LBZ back but the body style is getting a little long in the tooth for me, and I've gotten used to an 07-13 body, which I personally think its more comfortable. Having had 15 different duramax trucks over the years from lb7 to l5p. I'll keep the LMM as long as I can keep it running. My only complaint with the 01-10 generation was the soft rear springs and excessive sagging with a load, but that's easily remedied with a pack of 7/1 springs off rockauto making them perform like they should have from the factory. That and one day I'll throw another fixed vane on it and get rid of the vgt crap.
LBZ's are still hot commodities right, as is evident with the asking prices on the used market. Well it doesn't take much to make the LMM an LBZ wrapped in a new body. I'll leave it at that.