LML Duramax Questions

[Plowjockey]

Hello all first post here so bear with me. I'm currently looking at purchasing a 2011 2500 silverado w/61000 mi on the clock. I have searched the forums here and can't find anybody that has much to say about the lml, good or bad, I understand that overall driving style and maintenance is paramount in fuel economy and longevity but......... What's the real deal with these? I'm looking at long term ownership and love the silverados but I have reservations with all the emissions on the current duramax. Have personally driven the Lmm and was not too impressed with the economy. 1,040 mi from Helena Mt to Medora Nd I90 and I 94 average w 3 horse bumper pull 10.5 mpg. Pulled like a dream just no economy. Trailer w/1 horse didn't weigh over 6,000# ,empty maybe 15mpg. So is there anybody running lml's stock or with mods that will give me so information please?! Thank you for the great site and knowledge

[justlkn]

I have the 2012 LML so I don't speak from personal experience on the 2011. 2011 was the first year of the DEF addition. Based on other forums it appears GM had some unexpected issues with it. GM eventually released an ECM update that was supposed to correct some of the issues but on some trucks it worked and some others it did not. The concern I have for your purchase it that it is just out of warranty on the emissions. So if you do have a DEF related issue it is on your dime.
I would have them pull the service history and see if the previous owner was having issues with it. If not your probably good. My 2012 (knock on wood) has not had any issues whatsoever and runs like a dream.
Fuel mileage for me empty is 14MPG city and up 18MPG hwy if I catch a good tail wind. Towing a 15k trailer I get about 11.9 or so consistently.

Hopes this helps.

Glenn

[Plowjockey]

Thanks for the info justlkn, no mods yet I take it? I'm hoping that with 60,000 on it it's going to be broke in and pull decent economy but we shall see. Well with factory warranty available that's where I'm wondering if I have troubles with the exhaust emmisions system but the warranty is drivetrain so everything will be out of pocket for me with emissions issues! It just seems that these lml's are still a little too new, primarily looking at tune options nothing crazy just a small increase in power with a hopefully added benefit of some economy gains. With some exhaust work and or intake work also. Just wondering that's all ,keep it rolling in!!
Anybody know what the emissions system warranty is, the dealership monkeys can't give me a straight answer. Thanks

[justlkn]

Anybody know what the emissions system warranty is, the dealership monkeys can't give me a straight answer. Thanks


Emissions equipment is required by Federal law to be covered for five years or 50,000 miles.

Read more: http://www.motortrend.com/cars/2011/chevrolet/silverado/warranty/#ixzz2Nk8aFeie


And no mods to the motor. I did debadge some here and added some chrome there but keeping her stock for as long as possible. I bought her to work and that she does that well.

[Plowjockey]

Got any pics? I like the gmc better personally but some of the Chevys aren't too bad with a little modification. Well cruising the other sites out there everybody seems to want to turn everything into a 12 sec race truck that can tow 25k but that's not my intention, dpf deletes and tuners seem to be the order of the day however my interests are solely for drivability, longevity, and overall satisfaction. Have you had any problems with the def or the system? That's what has me concerned with the mileage of the pick up as its out of warranty. Holy buckets does anybody really need more than stock power levels for work, don't get me wrong I'm messing with my 95 as we speak and don't knock anybody for it, just not my thing with my main mode of transportation. Have you picked up on anything other than tuner & dpf deletes and if so what's the most user friendly? Cts, Efi live are the most I see with mbrp exhaust. How many miles do you have on your pickup?
I was kind of hoping that Kennedy would have something to say about tuners and such, since his latest addition, but haven't found anything yet probably waiting for warranty to come up as well.

[justlkn]

I don't plan on doing any mods to the drive train...at least yet. If I have any problems down the road I may consider removing some of the emissions stuff. The only mods I have done are adding mud flaps (I tow a lot and magically the rocks your tires kick up and hit your camper then bounce back and hit the tail gate causing damage) removed the bow tie off the back and the 4x4 sticker on the side, changed the front bow tie to billet, line-x'd the bed and put on a lockable hard flip cover. Other than that she is stock. Her nick name is J-Lo cause she has a fat #$%....lol Here's a couple of pics. I only have 12k miles on her and the only thing she has been in the shop for is a heater hose replacement. There is a TSB for it. The original one caused a vibration in the dash when she was cold that drove me crazy. There is a TSB for windshield noise caused by the window trim but I fixed that myself.

Billet Bowtie
2385

Hard Lockable trifold cover
2386

My baby doing work
2387

A pic of her fat rear and the mud flaps...lol
2388

[Plowjockey]

That's a nice pickup, I always thought curvy rears looked better than little ones! Anyways back to the pickup,I've heard that the regens where pretty well not noticeable other than a slight drop in economy, is that your experience also? One other thing what's your rpm at 75mph?

[justlkn]

When she regens I can tell. There is a slight noticeable change to the engine tone and the RPMs go up slightly at idle to around 750. I couldn't tell at first when regens would occur but after you get the feel for how she runs normally you will know when she regens. RPM shows around 1800 at 75mph.

[More Power]

....Have personally driven the Lmm and was not too impressed with the economy. 1,040 mi from Helena Mt to Medora Nd I90 and I 94 average w 3 horse bumper pull 10.5 mpg. Pulled like a dream just no economy. Trailer w/1 horse didn't weigh over 6,000# ,empty maybe 15mpg. So is there anybody running lml's stock or with mods that will give me so information please?! Thank you for the great site and knowledge

The LMM has been very good overall. Moderator Mark Rinker probably has more experience towing with one than many here, and other than a P0087 (due to high mile injector wear), his truck did a good job as I recall. He may chime in.

I'm curious how fast you drive, both towing and not. Speed plays a big part in fuel economy.

Jim

[Plowjockey]

Sounds fairly painless for regen, although I'm not to trilled about the bs involved with the emmisions I'm a fan of KISS, at least it's nothing that effects drive ability while in operation. But thus is progress I suppose just don't want a headache in the future, but I sure do like the new interior and quietness of the Gm 900 truck platform so that's what I'm looking at.
More Power, thanks for the reply. I was hoping Mark would stop by with some insight but none yet, it looks like he covers some dirt! The trip was pretty easy going speeds, on the 2 lane was 60-65 and the interstate was not over 70. I drove about 18 hours of the 24 hr trip, all night from Bozeman Mt out to Medora ND and then 4 hrs of shut eye and back. The cruise control was not used at all and my only complaint was the fuel economy, the pick up was a not mine but a friends, in had around 30,000 mi on it if memory serves. So maybe it wasn't fully broke in, but my 05 6.0l gasser cc/sb 4x4 same as the D-Max pulled the same horse trailer with approximately the same weight and got 12 empty and 10 loaded. This was however from Helena to Condon so a little more challenging pulling through the mountains, not that this is going to persuade me away from the Lml as torque is addictive, just expected a little better fuel economy with that trailer combination. Most of my driving will be empty anyway but will be towing more in the future and the price that the seller wants is hard to pass up. Ext cab/lb Lt with leather at $29000 is a pretty good deal to me.

[FTobey]

Our 2011 3500 drw crewcab has 30,000 miles and has been trouble free until the last couple of weeks. The message "Exhaust fluid quality poor" showed on the dash. No warning to add fluid, but I did because that is the only thing I could think of to do while on the road (Saturday and no dealers open). No change. Before we could complete our trip we were "Speed limited to 55mph at next startup". Monday our local dealer checked it out and determined that the fluid was indeed bad (I saw a cloudy sample), replaced the sensor that initiates cleaning the dpf (diesel particulate filter) and ran a regen of the dpf. Seemed to fix the problem, but sure didn't explain the cloudy fluid. But within 60 miles the same warning regarding fluid quality returned. A different dealer (because we were traveling) diagnosed the same poor quality fluid, flushed the tank, pressure tested for leaks and ran a regen of the dpf again. Seemed OK, but within 5 miles of the dealer the same warning came on again. The truck is now back with our hometown dealer who says Chevrolet's tech line is involved in finding a solution.

Has anyone had a similar problem and if so what was the fix?

[GM Customer Service]

Our 2011 3500 drw crewcab has 30,000 miles and has been trouble free until the last couple of weeks. The message "Exhaust fluid quality poor" showed on the dash. No warning to add fluid, but I did because that is the only thing I could think of to do while on the road (Saturday and no dealers open). No change. Before we could complete our trip we were "Speed limited to 55mph at next startup". Monday our local dealer checked it out and determined that the fluid was indeed bad (I saw a cloudy sample), replaced the sensor that initiates cleaning the dpf (diesel particulate filter) and ran a regen of the dpf. Seemed to fix the problem, but sure didn't explain the cloudy fluid. But within 60 miles the same warning regarding fluid quality returned. A different dealer (because we were traveling) diagnosed the same poor quality fluid, flushed the tank, pressure tested for leaks and ran a regen of the dpf again. Seemed OK, but within 5 miles of the dealer the same warning came on again. The truck is now back with our hometown dealer who says Chevrolet's tech line is involved in finding a solution.

Has anyone had a similar problem and if so what was the fix?

FTobey,

I’m sorry you are experiencing this issue. Please keep us posted of the results of your hometown dealer visit.

Feel free to PM us if you have further questions or concerns.

Louis (assisting Brandon)
GM Customer Service

[sooty]

how often do you refill the additive tank for the regen. and what does it cost to refill. Thanks .

[justlkn]

I get around 1000 miles a gallon. I tow alot so I think I may use a little more than others. Cost wise it is around 2 bucks and some change a gallon from the local truck stop but I prefer to buy the 2.5 gallon jugs of BlueDef at 12 bucks a box. 2 boxes top her off just right. The DEFtank holds around 5.5 gallons. The only reason I choose the more expensive method is I can prove I am using the GM approved DEF in case they want to say differently if a waranty issue pops up later.

Glenn

[kelloso]

I have a 2011 Sierra 2500HD LML so its basically the same truck as the Silverado. I bought mine used with 35,000 miles on the clock and I am pushing 45,000 in just a few short months having it. The mileage I am getting is really not to bad, average on highway empty is 20-22 when not in REGEN, 13 or so when its in REGEN cruising at 60-65. Towing my 28' TT I am getting 12-15 running 60-65. I use the BLUE DEF from any auto parts store and have gotten as much as 2000 miles out of a 2.5 gallon jug. All in all I will tell you that I absolutely love the LML, I traded a 2008 GMC Sierra Denali with all the bells and whistles and got the LML. I would never go back to a Gasoline engine. With the ammount of torque and horsepower in the new LML it will pull like a freight train. The only thing I am thinking of putting on mine is the Dura Mileage brainbox and see if it will give me the 4-7 MPG gain like it advertises.

2011 GMC Sierra 2500HD LML
2011 Grey Wolf 28BH
2005 BMW 330CI(Hers)
2010 Harley Davidson Road King Classic
2001 Harley Davidson Sportster 1200 Custom(Hers)

[LanduytG]

Just traded my 2011 LML 2 weeks ago for a 2013 LML. I had 83K on the clock. Over all economy on the hiway was 18.5 mpg. However I got 19+ on many occasions. City around 16-16 and towing 15K average was 11 and as little as 9.5 and 13 was the most. Life time regen average was 575 miles. Only issues I ever had was the DEF tank freeze issue for the early models. A reflash took care of that. Also had a couple of wire chafe which caused the NOX sensor to not read. I loved the truck for towing just set the cruise and drive.

Bought the 2013 because it got a great deal with all the incentives and GM employee pricing with my son in law. I have made one long trip with is 670 miles and got 18.6 mpg and it did its first regen at 600 miles. I see no need to add any tuner, this thing has as much power as I have ever needed.

Greg

[Frys6971]

Hi all, I know that i am asking qustion to a pretty old thread but I just made the switch from a 02 LB7 to a 12 LML. I bought my 02 brand new and had the best luck only had two issues, the campain on injectiors and the case saver in the T-case, I got around 15 on average in town and 17ish empty on the HWY. My new 12 has 70k on the clock and I am only getting 11.4 to 12.2 on the dash read out nothing like what you guys are seeing I will be pulling a 15k camper and it scares me that i am going to see 7-8 if that happens i will be bummed! My 02 pulling the same camper did 10.5 all day long at 65MPH! Is ther somthing i need to update or change to see the numbers you guys are? This is a very Newbe question??? How do i know when it is in REGEN mode, will it tell me? Also thinking about trying the Dura Milage brain box, they offer a great money back offer but if it hurts my motor then the $317.00 does not mean crap! Looking for some advise from you veterens!

[Kennedy]

It takes good fuel and good tuning to get the MPG out of these trucks. My mpg was pretty weak on my 2012 until I started tuning on it. I now have the pedal lag eliminated, it tows like an animal, gets much better MPG (upper teens) and far less frequent regenerations. All with the stock emissions intact.

I did also add lift pump and Mega filter to prolong fuel system life.

The Duramileage is back to the old harness box pressure fooler deal. This stuff has been obsolete for years now yet keeps resurfacing...

[Frys6971]

It takes good fuel and good tuning to get the MPG out of these trucks. My mpg was pretty weak on my 2012 until I started tuning on it. I now have the pedal lag eliminated, it tows like an animal, gets much better MPG (upper teens) and far less frequent regenerations. All with the stock emissions intact.

I did also add lift pump and Mega filter to prolong fuel system life.

The Duramileage is back to the old harness box pressure fooler deal. This stuff has been obsolete for years now yet keeps resurfacing...

What kind of tunnig have you done, I belive i have plenty of power for my pulling needs, just really would like to see upper teens in MPG. Dont get me wrong if more power came with better MPG i will take it!

[Kennedy]

I've been getting more and more conservative in what I do to my own trucks. I set my 2012 up with a very nice tune that does it all. The dead pedal is gone, it responds with less effort, but still runs clean and burns clean with less frequent regen cycles needed.

[BillBB]

I'm getting all of the same messages.

Check Exhaust System
Poor fluid quality

I went to the Dealer and they charged me $180. Said they reprogrammed the computer....

It lasted for about a week, and now all of the warning signs are appearing again.

2011 - 3500 HD with 26,000 miles.

Just six months past the 36 month warranty. WTF. Does anybody else have a better solution?:mad:

[DmaxMaverick]

Have a closer look at your powertrain and emission system warranties. The systems you are having issues with will be covered by one or the other. Your dealer okie-doked you.

[BillBB]

Are you sure that they are covered after 36 months? GM?

I actually have an extended warranty that I purchased separately and I think that I can now use it for a SECOND repair of the same item.

[DmaxMaverick]

The powertrain warranty is 5 years or 100,000 miles. The emission warranty is at least near that, in any state. Way longer than 3.5 years and 26,000 miles. A previous warranty complaint for the same issue will almost always extend that, too. Your extended warranty repair, if for the same thing, wasn't a "repair", and should have never been used for this. If it's a GMPP warranty, you're covered, easily. If the issue is the same, there'll be no deductible, as well. Don't let them tell you different.

[BillBB]

Thanks for the encouragement.

I'll let you know what I run in to.

[GM Customer Service]

Hi BillBB,

I understand that your issue returned after you visited one of our dealerships for poor fluid quality. I realize that this must be frustrating and I do apologize. Can I be of any assistance? I would be more than happy to look into this concern for you. Feel free to contact me my private message if I can be of any assistance.

Jennifer T.
GM Customer Care

[in4it]

Emissions equipment is required by Federal law to be covered for five years or 50,000 miles.

Read more: http://www.motortrend.com/cars/2011/chevrolet/silverado/warranty/#ixzz2Nk8aFeie



And no mods to the motor. I did debadge some here and added some chrome there but keeping her stock for as long as possible. I bought her to work and that she does that well.


Or until the District Manager decides that he does not want to warranty your truck anymore and decides to pull the plug on your extended warranty on unfounded reasons after almost 2 years of documented problems with the vehicle with no solution. GM does not have a solution to the problem and does not know how to correct the problem.