New to Forum: How to tell type of Engine

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The 2001-2004.5 model year Duramax 6600 is an LB7, and the vehicle will have a number 1 (one) as the eighth digit of the VIN. Injectors and injector fuel return lines are beneath the valve covers.

The 2004.5- 2006.5 model year Duramax 6600 is an LLY, and the vehicle will have a number 2 (number two) as the eighth digit of the VIN. Injectors and injector fuel return lines are outside the valve covers.

The 2006.5-2007 model year Duramax 6600 is an LBZ, and the vehicle will have a letter D as the eighth digit of the VIN. The 2006 model year LLY engines are said to be the same as the LBZ, except for power/torque rating, ECM & programming and emissions certification.

The 2007.5 - 2010 model year Duramax 6600 is an LMM, and the vehicle will have a number 6 (six) as the eighth digit of the VIN. This engine runs with a Diesel Oxidation Catalyst and Diesel Particulate Filter, and requires ULSD (Ultra Low Sulfur Diesel) fuel.

The 2011-2016 model year Duramax 6600 is an LML, and the vehicle will have a number 8 (eight) as the eighth digit of the VIN. LGH (late in this year range as the eighth digit of the VIN), and the vehicle will have a letter L as the eighth digit of the VIN. This engine runs with a Diesel Oxidation Catalyst and Diesel Particulate Filter, and requires both ULSD fuel and Urea.

The 2017 model year Duramax 6600 is an L5P, and the vehicle will have a letter Y (eight) as the eighth digit of the VIN. This engine runs with a Diesel Oxidation Catalyst and Diesel Particulate Filter, and requires both ULSD fuel and Urea.


More info and additional details on all of these engines can be found in one of The Diesel Page's content areas (i.e. see the Duramax 6600 Diesel Page to learn more).

Jim

[Kennedy]

I have a breakdown on my site under Dmax Performance. It covers the 06 LLY/LBZ debacle also along with VIN samples to show how to decode engine and model year.

[TJNE]

The 2001-2004.5 model year Duramax 6600 is an LB7, and the vehicle will have a number 1 (one) as the eighth digit of the VIN. Injectors and injector fuel return lines are beneath the valve covers.

The 2004.5- 2006.5 model year Duramax 6600 is an LLY, and the vehicle will have a number 2 (number two) as the eighth digit of the VIN. Injectors and injector fuel return lines are outside the valve covers.

The 2006.5-2007 model year Duramax 6600 is an LBZ, and the vehicle will have a letter D as the eighth digit of the VIN. The LBZ virtually identical to the earlier LLY, and in-fact, the latest LLY engines are said to be the same as the LBZ, except for power/torque rating, ECM & programming and emissions certification.

The 2007.5 model year Duramax 6600 is an LMM, and the vehicle will have a number 6 (six) as the eighth digit of the VIN. This engine runs with the newest emissions system, which includes a new Diesel Oxidation Catalyst and Diesel Particulate Filter, and requires ULSD (Ultra Low Sulfur Diesel) fuel.

More info and additional details on all of these engines can be found in one of The Diesel Page's content areas (i.e. see the Duramax 6600 Diesel Page to learn more).

Jim

How about the VIN digit for gear ratio? I'm looking into buying a 2006 Duramax LBZ 51,000 miles (would be my 1st desiel if I get it.) Anything I should know MPG, common problems, etc. I'm going to look at it tomorrow afternoon. I will use it to haul a travel trailer 5 or 6 times a year (Approx 7,000 lbs. now and maybe 10,000 lbs. I maybe in the market for a larger camper) Most of my driving will be around town, I drive about 7,000 miles a year avg. Looking for any advise I can get prior to purchase. Thanks in advance.
P.S. Vin# 1GTHK23D86F147471 What can you tell me?

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All of the 2001-2008 2500HD/3500 series Duramax diesel equipped pickup trucks got 3.73 gears. There is no other option. That said, the differential gear ratio is not found in the VIN, but in the RPO (Regular Production Option) code list in your glove box. There, you'll find a GT4 differential code, which is decoded as 3.73 (as well as lots of other 3-digit RPO codes).

If buying from a dealer, have them provide a warranty history for the truck. This'll let you know whether this truck has been a problem for its previous owner.

Good luck,

Jim

[TJNE]

All of the 2001-2008 2500HD/3500 series Duramax diesel equipped pickup trucks got 3.73 gears. There is no other option. That said, the differential gear ratio is not found in the VIN, but in the RPO (Regular Production Option) code list in your glove box. There, you'll find a GT4 differential code, which is decoded as 3.73 (as well as lots of other 3-digit RPO codes).

If buying from a dealer, have them provide a warranty history for the truck. This'll let you know whether this truck has been a problem for its previous owner.

Good luck,

Jim

I read on the Diesel Page that their are 3.42, 3.73, 4.10 gears in ref. to MPG and towing weights. Did I misunderstand or am I missing something? It recommended for towing heavy the 4.10's and for MPG 3.42's. Thanks again.

[DmaxMaverick]

I read on the Diesel Page that their are 3.42, 3.73, 4.10 gears in ref. to MPG and towing weights. Did I misunderstand or am I missing something? It recommended for towing heavy the 4.10's and for MPG 3.42's. Thanks again.

That applies to previous engines, 6.2L and 6.5L. It could apply to repowers of other vehicles (with a Duramax), as well. If the truck you are looking at is stock, it will have a 3.73. The Duramax trucks do very well towing very heavy with 3.73 gears, and do well on mileage with the same.