Chevy and GMC Duramax Diesel Forum banner
  • Hey Everyone! Enter your ride HERE to be a part of this months Ride of the Month Challenge!
1 - 19 of 19 Posts

·
Registered
Joined
·
206 Posts
Discussion Starter · #1 ·
Hey guys I am new to the forum, I have been doing quite a bit of reading but just had a couple of questions. Right now I own a 2010 GMC Sierra Reg cab short box with the 5.3L I really like the truck but am thinking about upgrading to a crew cab, and thought about looking into a diesel. For the most part I would use it for a DD, I drive 65 minutes to work daily (there and back) and in the summer time tow the fishing boat to the lake pretty much every weekend and usually head 6 hours north with a snowmobile trailer in the winter so the truck would be doing some towing. My question is right now with my truck I am getting 18.5 MPG driving to work everyday and when towing the snowmobile trailer north I am looking at about 9.5 MPG, with getting a diesel will I be sacrificing MPG? My father and his friends are also trying to talk me out of buying a diesel because they say you constantly have to be working them, and the MPG aren't that great. I would be looking at getting something used, the problem is I heard the LMM get worse MPG then the LML and it sounds like there is numerous problems with the LMM like the leaking trans lines, and dash rattle noise plus some other issues. I have found a couple good deals on LMM but don't want to buy something that might have issues since most of them are out of warranty by now. Which would you recommend getting? Not sure how much the total cost is to do the DPF delete but I would also be interested in doing this to if its worth the increase in MPG.
Thanks
 

·
Registered
Joined
·
341 Posts
I have a 2011 Not sure if that makes it a LMM or a LML, but I average driving back and forth to work which is only 8 miles away 14.2, If I can get her out on the open road and let the ponies stretch their legs out I'll average anywhere from 17.5 to almost 20 19.8or so. I bought the truck in Wisconsin and live in Arkansas it was a around 780 miles and I averaged 19.8 all interstate with the cruise set on 75Mpg. I pulled a 20' gooseneck trailer loaded with around 9k of round bales and averaged 14mpg. I haven't noticed any weird noises coming from it, I did buy it as a certified pre owned and love it. Hope this helps you out.

Oh I don't have mods on it either.
 

·
Registered
Joined
·
87 Posts
I traded my 08 Gasser in for my 13 Denali and absolutely love it and will probly never buy a gas truck again. I use mine mainly as a DD, don't do much hauling other then my 4-wheeler in the summer. Make the switch!
 

·
Registered
Joined
·
1,605 Posts
went from an 05 6.6L to this, and love it. Gets about 18.5 in town and 21-22 on the interstate with the deletes. Stock it was about 16 in town and 18.5 on the interstate roughly. I love the power these trucks have, it is amazing what they can pull and not even know its back there. The only negative thing i have to say is the cheap design of the leather seats. Mine are starting to bubble in the center. Just take it from me and condition them EVERY chance you get, and it should make a difference.
 

·
Registered
Joined
·
206 Posts
Discussion Starter · #7 ·
went from an 05 6.6L to this, and love it. Gets about 18.5 in town and 21-22 on the interstate with the deletes. Stock it was about 16 in town and 18.5 on the interstate roughly. I love the power these trucks have, it is amazing what they can pull and not even know its back there. The only negative thing i have to say is the cheap design of the leather seats. Mine are starting to bubble in the center. Just take it from me and condition them EVERY chance you get, and it should make a difference.
Ya I have seen some of the trucks have very rough leather seats in them for only being 2 years old!! That is one thing I don't like about leather seats. I am leaning more towards getting a LML, just tough to find one in my area that I like, have found a couple really nice LMM but they are out of warranty and it seems like everyone has had issues with the tranny lines etc. Sounds like the mileage wouldn't be much different then what I am getting now with my gasser. I would be interested in doing the deletes for better mileage but I guess it is illegal to do that in Ontario.
 

·
Registered
Joined
·
991 Posts
Just my opinion, id buy an lmm for sure! I did my deletes and my mpg rose! I am getting about 16-18 city, and 20-22 highway from 75-80 mph
Mine is bulletproof. No problems. My leather is looking perfect as well.
I likw the lmm because u can do efi live. And i think that is worth getting the barely older truck. U cant get efi live on an lml, which is why i like the lmm's and older only.
 

·
Registered
Joined
·
577 Posts
with the new tuning coming out i wouldnt let that really make my mind up anymore, although i do love my lmm and most likely would not buy something newer for some time being, if you are looking to do nothing to the truck and leave it stock id buy a new truck, warranty and new car smell, but thats just me (i wanted to tune so i looked high and low for my lmm, because at the time know one knew what the lml would do/no tuning for it)
 

·
Registered
Joined
·
342 Posts
I don't think you should worry much about leaky tranny lines. It's obviously one of the chronic problems but it's not every dmax that will have it. My dad has two 03's and between them two and my '06 we have had no problems. Even if you do end up with leaky lines there are aftermarket lines out there that fix the problem for good. I'm not sure what the tuning situation will be in the near future for the LML's but if you are looking for a moderate amount of performance and guaranteed tuning options then the LMM would be safest. If ur gonna stay stock...I've heard the LML' s are pretty sweet.
 

·
Registered
Joined
·
244 Posts
Get the LML. It is everything the LMM is but better. It has a true exhaust brake, beefier brakes and suspension and better mileage if you compare stock to stock and a stronger tranny. Now that there are tuners coming down the pipes the only real advantage for going with a LMM no longer exists as we will be able to get custom tunes just like the LMM.
 

·
Registered
Joined
·
667 Posts
I was looking at 2005 and newer trucks before I bought my 2011. I too came from a GM 1/2 ton with a 5.3. Great trucks, but I wanted (sometimes needed) more power for what I do.

I don't think you can go wrong with any year Duramax, but the price difference between an '08-'10 LMM and an LML wasn't enough for me to justify not getting the most current Duramax with a warranty and the newest bells and whistles. I would have been happy with the stock power of any generation Duramax, but I like the newer body style and other enhancements/gadgets these new trucks have.

At the time of purchase, I didn't care about EFI Live tuning and all the other things you can do to these trucks. Truthfully, I wasn't fully aware of what was available until I bought my truck and got more involved. Now that I've learned more about them, I still don't regret my decision. The future for the LML looks bright. :cool:
 

·
Registered
Joined
·
206 Posts
Discussion Starter · #13 ·
I don't think you should worry much about leaky tranny lines. It's obviously one of the chronic problems but it's not every dmax that will have it. My dad has two 03's and between them two and my '06 we have had no problems. Even if you do end up with leaky lines there are aftermarket lines out there that fix the problem for good. I'm not sure what the tuning situation will be in the near future for the LML's but if you are looking for a moderate amount of performance and guaranteed tuning options then the LMM would be safest. If ur gonna stay stock...I've heard the LML' s are pretty sweet.
Thanks, I was just worried that the LMM had a lot of issues, the biggest thing is I would like to get decent gas mileage, I understand it all depends on how heavy your foot is, how much roughly does it cost for the tuner and whatever else is needed to the the def/dpf delete? I would just be tuning for increase in MPG.
 

·
Registered
Joined
·
1,605 Posts
some have done the math and at $1100 for exhaust and tuner you recoup your money in about two years i believe. theres another thread that had that calculated in it.
 

·
Street Sleeper
Joined
·
614 Posts
I went LMM, easier tuning options, less to delete than the LML, and stuff like the trans lines there are kits ready made to fix the issue so its not like you are inventing a fix. Loaded with 10k - 12k worth of hay or equipment I still get 12-13mpg in my LMM on 33" tires. Far better than the 9 you are getting and I still have power for days moving that load. If you do any decent towing or driving the Duramax would be your best bet. Most people that try to talk you out of them only do so because they dont know or they think it is still some old 70's model GM diesel conversion. This is a whole new beast and it will make a beliver out of you and them when you pull with it passing cars like they are standing still and you have a load behind you.
 

·
Registered
Joined
·
577 Posts
Get the LML. It is everything the LMM is but better. It has a true exhaust brake, beefier brakes and suspension and better mileage if you compare stock to stock and a stronger tranny. Now that there are tuners coming down the pipes the only real advantage for going with a LMM no longer exists as we will be able to get custom tunes just like the LMM.


id disagree slightly...

CP3>CP4 just for tuning purpose alone... kory was draining the rail at a 525ish hp tune with a lift pump already on a lml, ive herd of guys running north of 600 with stock CP3 with 40's+ sticks on lmm's.. just my input
 

·
Registered
Joined
·
1,155 Posts
id disagree slightly...

CP3>CP4 just for tuning purpose alone... kory was draining the rail at a 525ish hp tune with a lift pump already on a lml, ive herd of guys running north of 600 with stock CP3 with 40's+ sticks on lmm's.. just my input
This is true ^

Also, DSP tunes are not going to work with an lml.

That being said, I would still buy an LML if I didn't already have an LMM. 500rwhp is enough to play with while more advancements come out for the LML.

But, I sure as hell wouldn't trade my LMM for an LML.
 

·
Street Sleeper
Joined
·
614 Posts
^^ I agree more with that last statement you made...making my LMM the way it is was far easier than it would be to duplicate with a LML. I would not trade my LMM if you hand me the keys to a brand new LML for free...it is just that good of a truck. But thats just my opinion.
 

·
Registered
Joined
·
577 Posts
This is true ^^

That being said, I would buy an LML. 500rwhp is enough to play with while more advancements come out for the LML.

Oh yea 500 is more then enough, just going to cost an extra $2500+ to do another fuel system like they did on the 6.7 furd id rather spend that on a set of injectors for safety on tuning a twin setup
 
1 - 19 of 19 Posts
Top