# Which duramax motor is your favorite?



## Browning01 (Apr 21, 2010)

I am going to buy a 2500 with a duramax here in the next month or two.  I dont do much towing but I will probably lift it and put a mild chip in it until I have enough for a tranny to run an extreme tune like efi live.  Who of you has one or have owned multiple different years?  I like the LBZ for more power and the lly too, I know the LB7 is good I just dont want to deal with the injector problems even though they are warrantied to 200k.  Which tranny felt the best to yall?  The 4 speed, 5 or 6 speed?  Ive read about the different motors on the diesel forums I just wanted to get some of yall's opinions.


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## bsthonda2010 (Apr 29, 2010)

i think lbz is the best motor as far as fixing up for power, and also it has the 6 speed transmission, which will last longer than the 5 speed with a programmer. you can get efi live in many different tunes, and its actually the best way to program your truck, safest if you get a good tune from someone


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## Tulip (May 1, 2010)

Stay away from the lb7. I have a 2002 that has 5 bad injectors and is out of warrenty because of age. Only has 120000 miles on it. Boco bucks to fix.


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## SWS (May 3, 2010)

iv only dealt with the lly and its been a purty good engine. iv put almost 60k on it pulling a 5th wheel from NM to GA multiple times with a PPE standard tuner. Iv yet to replace anything on the motor, but have had my issues with the 6speed ally and third gear slip. great engine if only the ally could handle the power.


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## nosfedgta (May 10, 2010)

SWS said:


> iv only dealt with the lly and its been a purty good engine. iv put almost 60k on it pulling a 5th wheel from NM to GA multiple times with a PPE standard tuner. Iv yet to replace anything on the motor, but have had my issues with the 6speed ally and third gear slip. great engine if only the ally could handle the power.



get you a 100.00 transgo JR


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## quackhead1 (May 16, 2010)

LBZ hands down


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## ARbowhunter7 (May 16, 2010)

They are all a little different, but you can't really go wrong with any motor. The LB7's (01-04) are notorious for injector issues, but swap in a set of quality injectors from Dynomite Diesel or Industrial Injection and don't worry about it again. The problem in a set of new sticks will run you about $5,000 installed for a Duramax. The LB7's have the strongest pistons (many LBZ Duramax sled-pullers actually swap in LB7 pistons for reliability) , but also the lowest power rating from the factory, as well as a standard geometry turbo, unlike the LLY and LBZ which run VGT turbos, which keep the exhaust note quieter (when straight-piped, sounds like a fighter jet), and whistle a lot louder. 

If there was a Dmax to stay away from, it would be the LLY (04.5-05, plus some overrun 06's, but they are rare). It's a great motor, but many have overheating issues that the General won't warranty fix. You can fix this yourself with a V2 kit from Adrenalin Truck Performance, but it ain't cheap. The LLY does benefit from an external (relatively) injector design, so you can change out injectors easily as well as a hotter injection pump from the factory so it makes more power. 

The LBZ (06-07 Classic)  is a great, quiet motor that makes a ton of power from the factory and is backed by the 6-speed Allison. The only complaints about these motors are the pistons. Some have cracked with hot tuners, like a PPE HOT+2 or some hotter EFILive tunes. 

I would stay away from the newer motors (LMM, upcoming LML) because of the newness and problems of the DPF Filter and Urea injection (LML).

The Allison transmissions are both good (5 speed and 6 speed, they never offered a 4 speed), but with the 6 you get great gear selection and lower RPM's on the highway. 

For mods, no matter what anyone tells you, the ABSOLUTE FIRST THING YOU GET is a good set of gauges. NO matter what and ALWAYS WATCH YOUR EXHAUST GAS TEMPERATURES!!!!!!!!! If you're towing and she gets to 1300 degrees, back off.  Then you get a good turbo-back 4" exhaust and an intake. 

     The programmer is your choice, I've owned them all. You mentioned EFILive, which tells me that you've already done research. I'd start with this. You can run soft tunes with this until you get your tranny built. Get in touch with Rob at Adrenaline Truck Performance or Nick at DuramaxTuner.com. They're the best out there.Then step up to a hotter tune and a lift pump. This, plus maybe a bigger turbo, is as far as you can go and still have a reliable daily driver. 

     These mods, done right, will put you in the 550 rwhp range...any higher on a Duramax and you risk internal engine damage. I made this mistake with my LB7. I kept adding go-fast parts until it was no longer reliable to daily drive and tow with. It's now a very expensive dedicated weekend toy/sled-puller.

My current work truck setup is a 2007 Classic LBZ 4x4 Crew Cab. It has a 7" BDS lift, 35" Mud Grapplers, and 18" XD Series wheels.

It has MBRP 4" exhaust, and a PPE intake. I run EFILive from Nick at Duramaxtuner.com, a Suncoast Stage IV transmission with billet shafts and a billet converter custom built by Garmon's Diesel Performance. It also has a Raptor 150 lift-pump and tie rod sleeves from CrankItUpDiesel.com. This setup is great for daily driving/towing and makes 504 rwhp and 1007 lb/ft of torque at the tires on the dyno. 

Hope I've helped you with your choice, and if you have any more questions, feel free to PM me. I'll be more than happy to answer any question you may have.


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## mstew (May 17, 2010)

love my LBZ. gotta 06 with the ally, superchips programmer and have had no problems. truck has 6 in lift with 35 in tires. went from 11 to 18 mpg with the tuner.


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## stev (May 17, 2010)

lbz


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## Mark Brooks (May 17, 2010)

LLY- Overheating is not a consistent problem.  Injectors are easy to get too, but rarely have to be changed.

2004.5 and 2005 are best Durmax's in my opinion.

140k on my 05 Crew Cab 4X4 and only issue was injector wire change under warranty.  

MB


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## ARbowhunter7 (May 17, 2010)

Mark Brooks said:


> LLY- Overheating is not a consistent problem.  Injectors are easy to get too, but rarely have to be changed.



They're not a problem at all if you've never had one that runs hot. If you worked on diesels regularly, you may notice it more

Also, the problem is common enough for a very expensive fix (the V2 system) to have evolved to near perfection and for a whole company to be based on it's sales. As stated before...if there were a Duramax to stay away from it would the the LLY. 

As for your recommendation of the LLY over others, what reasoning for this do you offer? The LLY is essentially the same as the LBZ, except the LBZ is more efficient, quieter, more powerful, and comes with a superior transmission. And there is STILL a chance you will get an overheater with the LLY.


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