From 01 To 07 What Was The Best Duramax

yukon25008.1 · November 11, 2010

i might end up going back to a pickup, we found an unbilievable deal on an 03 z71 tahoe so it makes no sense to have to suv,s in the family.. so if its not an 8.1 truck id like to go back to a duramax because i d use my vehicles to work and use the 2500 part of them..

ive had an lly duramax and wasnt so impressed with power and mileage, the body stlye i want is an 03-07 sierra. which limits me, just curious on peoples opinion

mxdirtrider56 · November 11, 2010

LB7 for sure. If I was going to buy a used Dmax it would have the lb7 motor. They had some injector issues that were covered under an extended warranty but they are the best for getting tons of power out of em.

BlackSilver · November 11, 2010

I put 150K on an LB7 - replaced injectors twice.

I put 100K on an LLY - ran hot.

Now have 75K on an LMM. Awesome! Way stronger, and no issues at all. It's been perfect.

yukon25008.1 · November 11, 2010

i heard the lb7 was better, like i said the lly i had wasnt impressed but i have nothing to compare it to.. when did the lb7 stop?

i thought the lly started in 04.5... so i could get lucky and find an 03 sierra hd an be ok,, id like to try newer but cant really swing the price now for an lmm.

yukon25008.1 · November 11, 2010

How big of a pain in the ass/cost is the lb7 injector issue?

mxdirtrider56 · November 11, 2010

LB7 motor was in 01-04 trucks.

yukon25008.1 · November 11, 2010

so if i came across an 04 silverado or sierra how do i tell if its an lb7 or lly.. if it started in 04.5... does the vin tell, or can you physically tell looking under the hod

04JJHD · November 12, 2010

Should be the rpo code in the glove box such as lly lmm and so on

vettelovralexand · November 12, 2010

so if i came across an 04 silverado or sierra how do i tell if its an lb7 or lly.. if it started in 04.5... does the vin tell, or can you physically tell looking under the hod

8th digit of vin tells the engine. Here is an excerpt from dieselplace talking basics of the engines:

Years 2001-2004 come with the LB7(8th digit of VIN is 1) motor that produced 300hp and 520ftlbs at the flywheel. The majority of the programmers for this model will not work on later models and vice versa, however the the Quad Stealth2 tuner is now one tuner that works on them all from 01-05. This model may or may not have a catalytic converter depending on where it was sold, but there is no egr or other electronic equipment as far as I know. These are known to provide better mileage and a bit more power with mods.

While the LB7 was still in production throughout most of 2004 we started seeing the arrival of the new LLY(8th digit of VIN is 2) motor that produced 310hp and 590ftlbs at the flywheel in January of 2004. This motor is the first Duramax with equipment from the factory to meet 2007 emissions standards. It has an egr valve, catalytic converter, and a host of other electronic additions and programming. It is referred to as an 04.5 and this motor remained until late 2005 when it was replaced by the 06 LLY. Programmers for 04.5-05 LLY’s will work on each other, but will not work on LB7 or later models.

Year 2006 introduced a newly revised LLY(8th digit of VIN is 2) and a completely new LBZ(8th digit of VIN is D) motor. The 06 LLY has the new Bosch 32-bit computer and torque goes up to 605. The 06 LLY has the same block as the new LBZ, but without the enhancements. The 06 LBZ also has the new Bosch 32-bit computer along with different programming and internal motor enhancements to handle the increased power and torque it is rated at. The 06 LBZ is rated at 360hp and 650ftlbs at the flywheel. Programmers for the 06 LLY will work only for this model due to the new Bosch computer, but rumor has it that programmers will work for both the 06 LLY and 06 LBZ computers since they are the same units just different programming. Programmers for the LLY and LBZ will not work with previous Duramax computers/engines. The 06 LLY and LBZ also come with a 6-speed tranny

Short and sweet

LB7 - 520tq 300hp

04.5 LLY - 590tq 310hp

05 LLY - 605tq 310hp

06 LLY - 605tq 310hp

06 LBZ - 650tq 360hp

jro909 · November 12, 2010

i never realised that the dmax had so many different engine rpos...what was so different between all of them? i was always under the assumption that they were all the same 6.6

yukon25008.1 · November 12, 2010

i knew there were diffrent/newer versions.. but just thought it was to make more power to compete w the cummins, and powerstoke..

but i remember guys saying that emmisions stuff kept getting added, so being that the lb7 makes the least power and torque,is it the easiest to upgrade and/or program??

jf781 · November 12, 2010

From what I've heard the LBZ was the best Dmax. Did some work on the injectors to solve the some issues with them sticking open. Also like mentioned above came with the 6 speed transmission. It was also before they started putting DEF on them so that will help with milage as well.

My $.02 is that I would not look at anything other then the LBZ just cause of the injector issues. If they go I believe they get stuck open which will grenade the motor (can't compress liquid). If I'm wrong please let me know but this is what I have gathered from the interweb.

vettelovralexand · November 12, 2010

i knew there were diffrent/newer versions.. but just thought it was to make more power to compete w the cummins, and powerstoke..
but i remember guys saying that emmisions stuff kept getting added, so being that the lb7 makes the least power and torque,is it the easiest to upgrade and/or program??

It is generally the choice for those that are out looking to make the most power without digging into their engines. If you are looking for the one that will be the easiest and most powerful when tuned, look no further than the LBZ. They are as fast stock as what either of the other two are with (small) programmers with virtually none of the associated turbo lag. I love the way the LBZ feels when driving as compared to the other two. Every year the allison was improved and got smoother and smoother and the LBZ makes amazing power. They each had some issues, but the LBZ is what I would buy. (My dad has both an 05 LLY and an 06 LBZ which he purchased after having 2 2001 8.1L trucks, all of which I used on a regular basis until I got a truck of my own.)

Bluedog · November 12, 2010

Owned at least one of every flavor... the LMM beats them all hands down, even with the DPF system (which has been seamless as far as I'm concerned and not nearly the problem some make it out to be).

Second best was the 2006 LBZ - too bad the rest of the truck was such a POS.

GM put two sets of injectors into one of my LB7's (2003), and one was leaking again when I traded it in. That engine was the weakest of all as far as pulling and smoothness. Lots of turbo lag and with the 5-speed Allison it seemed to never be in the correct gear loaded with my camper going over the mountain passes.

Try for a LBZ if you can't afford an LMM.