I have no experience with LBZ/LMM but yes, those would be the years I would go for. LBZ is essentially a tuned from the factory version of the LB7/LLY years. LMM is the way I would go if I was looking to trade in my current DMAX. I have an LB7 and I carry around a small parts store in my toolbox out of necessity. Granted it’s a 21+ year old truck, it’s never left me stranded with something I couldn’t fix right there on the side of the road

 

I purchased my 2008 LMM used in 2009 and the only major repair was to replace a leaking EGR cooler, repair cost about $700. Other than that, it has only required maintenance and upgrades, lift pump, tune. I pull a 12K trailer anywhere I want to go at any temperature. If it were me, I'd try to find a 2010 LMM. They seem to be the best of the LMM family as far as problems and required repairs go. LMM's have the CP3 high pressure pump, not the problem prone CP4. I suggest that you use additional lubrication in the fuel.

 

Been driving my LB7 for 20 years on 3/23/2022. Has 426k miles. Can't speak for the LBZ and such but I'm not afraid to go anywhere, anytime in my truck. It's been extremely reliable - even down to the injectors that fail - reliably - every ~80k miles LOL. But other than that, it's been mostly wear and tear type repairs.

 

I had 2 LMMs. Both 2008 models. My first one i got practically new, only had 9000 miles on her. It was a crew cab long bed Z71 GMC. Not one problem with it. I was an idiot to get rid of her, but I was strapped financially at the time. My second LMM I got with about 180,000 miles on her. I put an additional 30,000 miles on her before i sold her. She did very well, was maintained well by the previous owner as well. The DPF was getting a little tired as the regens were down to about every 350 miles instead of every 450 miles, but still did great. I started to get a bit discouraged when the rust/rot above the rear wheel wells set in and I found an opportunity to sell her and get what I thought was a fair price for her at the time. Only problem I had with it was the fuel filter housing was not holding pressure in the summer. I fixed it temporarily by getting a new bleed screw but I think the lines going into the fuel filter housing were starting to go. That's to be expected. Shortly after selling the LMM I got me a 2018 L5P also practically new, had about 11,000 miles on it. Prime condition. I have her now and she has almost 38,000 miles. Runs great.

I did have a 2012 LML for about a year. I would not recommend them. DPF and DEF issues, NOX sensors, glow plugs. All under 100,000 miles.

 

I did have a 2012 LML for about a year. I would not recommend them. DPF and DEF issues, NOX sensors, glow plugs. All under 100,000 miles

I would like to hear if people with deleted LML, with the lift pump "upgraded" would recommend them

 

We don't talk about emissions deletes on this site

 

In 12 I bought an 11 LML with 40k on it. I bought it in NC and it was the brother of the owner of the dealer that had it. I got a maintenance record on it and there was a few minor repairs that were done to it before I bought it. Really off the wall stuff that you never hear of needing repair/replacement. Around 50k is when I started having issues with it. All emissions related. Truck was never driven in the winter and was stored in my heated garage during the winter. I did have one issue with the TCM and that was replaced under warranty. I dumped that truck at 65k in 2015 and bought a 2015. It currently resides in my heated garage during the winter months, has 22k on it, and spring of 2021 it had to get the DEF heater replaced (the entire sending unit). Just last weekend I installed a Fleece Performance lift pump and primer bulb delete. I run a fuel additive every tank fill up and have with this truck almost since day 1. I never ran any additive with the 11. Knock on wood, and hopefully it stays this way, but I have not had and emissions issues like NoX sensors, EGR, etc.. BUT the truck has 22k on it. Time wise its lasted longer than the 11, but mileage wise it has a way to go yet.

 

I picked up a used 2008 back in 2009. Got 190k on it and doing great power train wise. Had some recent issues with databuss modules but finally got it resolved. Get a decent lift pump and invest in an S&B 62 gallon tank. Best money I ever spent. I'll run my LMM till the wheels fall off. Runs even better with mods we don't talk about here. Dean

 

My LBZ has 300,000 plus miles, no issues. LMM has 600,000 miles plus, waterpump and thermostats.

Both trucks do have some dead glow plugs (LMM are all dead) but they start fine.

Unless ya get crazy with tunes, Duramax's are kinda hard to kill.

 

Although I'm new to the Dmax platform as an owner, I've built many a gas motor and worked on a few diesels throughout the years. One thing i will say is when these motors are engineered, they are built to maintain reliably and over engineered in certain aspects for tolerances. Although diesel performance is a huge market, arguably because changing simple engineering aspects will yield more power, you do have to be mindful when doing upgrades. Whem you reduced those tolerances, it leaves room for failures.

Every generation Dmax has its silly quirks. You aren't dealing with anything major from the beginning like the Ford 6.0s had, but injectors and pumps are know to fail earlier than you would like them to. If you maintain proper basic maintenance and just run them hard, youll be fine.

I recommend trying to buy the best combo of newest vs mileage you can find. The LBZ platform had very limited production and are highly sought after. This is primarily because that was the last generation before highly regulation emission components became standard. Ever since, the various emissions components have become the Achilles heel for these motors. Its federally illegal to remove any of these components so that's not even an option anymore, nor does any member of this site condone or promote the same, and its not allowed to be spoken of.

If searching for one used, try your best to find one unmolested. Yes, these can be 700k trucks no problem, but when you purchase one at 250k, you dont know how it was treated in that first 250k. Once you start seeing charge pipes and dps5 switches etc, i would be learly to pull the trigger unless you get paperwork for EVERYTHING. Again, not to say the previous owner didn't do it properly, but thats now YOUR investment and you want to make sure your baby is taken care of, right?

There is a lot of knowledge around this place. Each generation motor has its own subsection in here so just poke around and feel out common issues. Take it with a grain of salt though because most posts are people looking for help with issues, that doesnt mean every guy has these issues all the time - but its can help give you basic knowledge of commonly seen issues.

If you dont know, just ask. However try to do some searching and digging before you ask the same "what size wheel and tire will fit my truck" that is posted 60x per day. Etc.

Good luck and keep us posted!

 

If you dont know, just ask. However try to do some searching and digging before you ask the same "what size wheel and tire will fit my truck" that is posted 60x per day. Etc.

AMEN!!

 

I bought an 07’ LBZ new. I owned it until Jan 2021. I only had one glow plug fail in all the time I owned it. It was likely the best truck I’ll have ever owned.

 

I have a 2011 LML with around 1.1 million on it. The odometer stopped at 999,999. I did a head gasket, turbo, transfer case, and rebuilt the rear end. Is the only major repair. Still has the original a/c compressor and alternator on it and fan clutch. However I did park it in Mexico around 200,000 and some parts were stolen. Still running today.

 

I have a lowly LLY that has never let me down in the 12 years I've owned it. Usual stuff, water pump, injector harness fixes, 1 glow plug, front wheel bearings, It only has about 145K miles, but about 1/3 of that has been pulling a heavy Arctic Fox 5th wheel. Did a preemptive trans upgrade/pump rub fix about 7 years ago. Stock height and still has the original head gaskets, EGR and PCV setup. I do nearly all my own maintenance and upgrades and can diagnose potential issues with a V2, I just upgraded the Pitman/idler to Kryptonite, at age 78 that stuff will no doubt outlive me.... No DEF, no DPF and no payments. Most reliable vehicle I have ever owned, it is my "forever" truck.

 

I am the proud and happy owner of an LMM dually that I purchased new. It is my daily driver and I use it to tow a 17k 5vr. I have towed the 5vr up and down the east coast and through the Appalachian mountains without any issues.

The only things that has ever broken on the truck are the TCM, one glow plug and the fuel filter head. I use Mobil 1 oil and put in Opti-Lube with each tank of fuel.

The drive train on my truck is bone stock and is without a doubt the best vehicle that I have ever owned. When I first got the truck I did a ton of research about modding the drive train but could not make the business case to offset the expense of the mods. In hindsight, I am glad that I left everything alone as it continues to do what it was designed for without issue.

Regardless of what truck you may buy, proper and timely maintenance is the key to the longevity of any diesel truck. Without maintenance records, I would walk.

Obviously, I vote yes for the LMM.

Happy shopping.

 

I'm new here but I'll pass on what I know.

Injectors are supposed to fail every 80K (mine haven't in 15K from 152K to 167K that I've owned my LBZ).
Prior to LBZ (I think) changing the injectors is supposed to be a pain in ass (expensive), LBZ and later are supposed to be fine. Perhaps someone else with actual experience on that can weigh in, I'm just passing on what I've been told.

The turbo's will get stuck, the variable vanes get stuck. It will give you crappy fuel economy, throws a code, I've been running mine like that for 15K miles. It's a 13 hour by the book job to replace the turbo. Turbo is about $1500 not marked up so expect somewhere in $4-5K to replace it.

Other than that, fantastic truck.

 

Injectors are supposed to fail every 80K

The turbo's will get stuck, the variable vanes get stuck.

That's the first time I've heard that about the injectors and turbo.. I must have been missing something these past 11 years

 

About 250k into my 07.5 LMM.
I've done a bunch of upgrades but never because something failed.
With proper maintenance and don't push it too hard it will be a long lasting truck.
If interior is most important to you, LMM wins.
If you live in an area or state where you cannot delete or tune, or you don't wanna do it, go LBZ. If you are looking to tune and delete, go LMM.
Another little difference is LMM transfer case is better built OEM than LBZ. However you can build LBZ to be better than it is.
My thoughts.

 

There are so few DPF issues reported on here for the LMM I can't see why deleting it would make sense.

 

Because they run better and make better as mileage. D

 

The lbz has better power output, or let's say more usable power than lmm due to the DPF. The engine had to have more power output so they could afford to put such an engine strain on the truck. Use a stock lmm, then turn around and use the stock LBZ and you'll feel a bit of difference in the lbz's favor.

 

If you buy an old one you'd better have a mechanic on standby or have a big toolbox. FYI Buy new w/ 100,000 mile warranty and trade w/ 95,000 miles! Diesels take a lot of care. If you don't want the maintenance, buy gas

 

278k on my 2016 LML purchased new. 1 EGT sensor and 1 DEF pump and that's all I've had to replace. Ive done some upgrades because I waned to but its been the most reliable vehicle I have ever owned.

 

Interesting comments on the injectors. A friend bought a 2017 in part because many of his FedEx client run Duramax engines in their delivery vans and report 5-600k miles before any injector problems. I hope the same holds true on my LLY with 206k miles, original injectors. My diesel wrench tells me that hes got other people with LLY's getting 500k miles before any injector issues. He does advocate running BG 245 every 10-15k miles and then some kind of fuel supplement periodically.

 

I have enjoyed my 08 Duramax. I have

I tend to agree. Never heard of a normal life limit on the injectors or turbo vanes. I have heard of issues some have had regarding the variable vanes being stuck on their trucks before but not what I would call a common problem with the Duramax. Got 190K and my original injectors are still going great, same for the turbo/vanes. Had to change out a couple of glow plugs over the years and that is about it for my LMM. Dean

08 Durmax LMM, replaced injectors. Posted thread about it. You definitely need a OBD reader for resetting any fault that puts the truck in reduced power mode with a trailer. That could be the biggest headache on freeway @25mph. For LMM, injector life is approx 150k from what I have read.
Love my truck, don't see it departing without me! Mark

 

Duramax is junk. $10,000 to replace failed head gasket at 123,000 miles. 2008 GMC 3/4 ton.