I just registered and have been trying to find info in the forum about the designation LLY. I bought a 04 GMC 3500 DRW in July. Love the truck. Great power! In my owners man. it only mentions the LLY designation when talking about the glow plugs being fast warmup, and mine sure does start quickly. My engine code is a 2 (the 8th number as I hear is the engine code). Do I have a LLY engine? What is the difference between the LLY and the other Duramax? I looked around in the forum, but didn't see anything about this. Hope I'm not asking a question that's already been answered. Thanks
Doug

8th number 1=LB7 2=LLY

Tons of info here. Grab a beer, spend the night!
Pete

short and sweet...

LLY is 310 HP and 590 Torque, New changes to engine= Variable Geometry Turbocharger(Hydraulic Actuation) · Revised Fuel System with New Injectors (Smaller Injectors that are more reliable and more servicable) · Two-Piece Rocker Covers (No removal of Valve Cover to access injector) · Fast-Heating Glow Plugs and Controller · Improved Engine Control Module (ECM)(32 Bit) · Revised Air Induction with Resonator(Quiter intake) · Improved Water Pump(Higher Water Flow) · New Cooling Fan Ratio(Faster Fan Rotation) · Revised Oil Pressure Sensor (Changed position on Oil Pan) · Cooled Exhaust Gas Recirculation (EGR) for All Applications · Catalytic Converter for all Applications

hmmm, motor sounds real nice until the last two lines. think I'm keeping LB7

Isn't the torque on the LLY 605?

Isn't the torque on the LLY 605?
in 2005 - 605

in 2004 - 590

(or maybe there was a better test in 2005??:ro) :) )

Thanks to all for the info. So I do have the LLY engine. So far I've been very pleased with the truck. Only problem was AC not cooling properly with outside air selected. GM has come up with a service bulletin and fixed the problem under warranty. Havn't had any really hot weather lately to check out the fix, but hope it's better. Gets hot here in Houston!

OK, here’s one. If the 2004.5 is the same engine as the 2005 AND if you get the latest ECM software, does the 2004 have the same torque as the 2005??

Yes it is the same engine. I've heard that the torque increases are on paper only. In other words, same programming/same engine.

OK, here’s one. If the 2004.5 is the same engine as the 2005 AND if you get the latest ECM software, does the 2004 have the same torque as the 2005??


are you talkin about the ECm software is that what the (computer reflash ) is?

I think with that EGR and cat thing I will keep my 04 LB7 as well.... No need to restrict the motor anymore...