I sold my 06 2500HD short bed LBZ engine truck and bought a 04 2500HD extended cab, long bed.

I bought the 06 LBZ new and put 27K miles on it

The 04 LB7 had 42K on it when I got it and have put 4K on it sofar.

POWER Noticable less in the 04 especially in the very low RPM range
NOISE The LB7 is alot louder especially at low speed and idle
TRANNY The 5 speed LB7 seems smoother to me than the 6 speed LBZ
STARTING The LB7 starts harder than the LBZ, more cranking
MILEAGE I drive back and forth each weekend from one town to the next, 177 miles 1 way, mostly interstate @ 70+ MPH. Hand calculated, the best I ever got in the LBZ was 16.3 MPG and I would say average was 16. The LB7's best was 19.8 MPG and I would say average is 19+. The LB7 also seems better in everyday driving. On my trips guys, the LB7 is 3 MPG better which adds up when diesel is at $ 3.

The bottom line is I think the LBZ is much more powerful and refined than the LB7 but you have to feed the beast and with diesel going to $ 4+ shortly, this is a consideration.

M

If she's cranking hard, check the batteries, these diesel's do tend to wear them down quick. Add a signature too please.

Good post. Why did you decide to sell your LBZ?

The 06 LBZ truck was a short bed extended cab. I REALLY needed a 8' bed. I listed the truck on Ebay and sold it and was then out a truck.

Purely for cost, I looked for and found a used truck. I found via Autotrader a 04 LB7 engined (didn't want a LLY) extended cab, long bed, loaded (LT3 package) with 42K miles with clean carfax and VIN check showed no issues.

When I got it here, I changed motor oil out with Mobile1 Turbo Diesel, put in a K&N filter, changed the tranny oil and filter and used Allison TransSYND oil, changed the fuel filter, had the injector balances looked at by Chevrolet (good numbers) and took the Firestones off and put on 265 75R 16 Michelins. I also put in a Sirrius integrated sat radio to the GM radio.

NICE TRUCK, well pleased and really happy with the fuel economy.

Thanks for the post. Been thinking of swapping the other way up to an LBZ, but maybe I'll just hang on.

The LBZ is a fine engine and the 6 speed is good too. I just think you would pay for the power with more fuel based on my experience.. If the fuel economy was even, I wouldn't of been as happy trading backward.

Good info...:)

Mike,

After reading your post I agree with your entire thought process with the excetion of the hard starting. I should rephrase and say that I'm a little confused, my 03 Lb motor starts real easy and was even pretty fair tempered in the winter months, my old gas 350 is the only thing I really have to compare to and it starts pretty easy. Someone else mentioned battries but I would also wonder about glow plugs and that sort of thing.

What made you put in a K&N, thought about it on mine but was worried about problems with sensors. How's it been working with yours? :confuzeld


Either way I hope your happy with your new truck. :)

Nice post.

Hard starting is compared to the LBZ engine. The LBZ, the glow plug light was only on a secopnd or so then I hit the starter and it hit right away, well under 1 second to light. This truck, the glow plug light stays on longer (no big deal) but when I hit it, it takes more than a second of cranking for it to hit. Don't get me wrong, it starts just fine. I was making an observation that the LB7, or at least my LB7 is a little harder starting than the or my old LBZ.

The K & N went on and no issues. Unfortunately, I didn't drive the truck enough with the stock filter to be definitive on the K & N performance.

We have a 2006 LBZ 3500HD with 8K miles. I now have an 04 LB7 with 45K miles.

I was wonderin.. sure like that quiet LBZ engine and 6 speed.

EZ Swap or a nightmare ??

What made you put in a K&N, thought about it on mine but was worried about problems with sensors. How's it been working with yours? :confuzeld

No problem with the sensors on mine, had a K&N on the '03 since it was new. Gained a mile and a half to two miles to the gallon when I installed one on the '96.

I sold my 06 2500HD short bed LBZ engine truck and bought a 04 2500HD extended cab, long bed.

I bought the 06 LBZ new and put 27K miles on it

The 04 LB7 had 42K on it when I got it and have put 4K on it sofar.

POWER Noticable less in the 04 especially in the very low RPM range
NOISE The LB7 is alot louder especially at low speed and idle
TRANNY The 5 speed LB7 seems smoother to me than the 6 speed LBZ
STARTING The LB7 starts harder than the LBZ, more cranking
MILEAGE I drive back and forth each weekend from one town to the next, 177 miles 1 way, mostly interstate @ 70+ MPH. Hand calculated, the best I ever got in the LBZ was 16.3 MPG and I would say average was 16. The LB7's best was 19.8 MPG and I would say average is 19+. The LB7 also seems better in everyday driving. On my trips guys, the LB7 is 3 MPG better which adds up when diesel is at $ 3.

The bottom line is I think the LBZ is much more powerful and refined than the LB7 but you have to feed the beast and with diesel going to $ 4+ shortly, this is a consideration.

M

Were the rearend ratios the same?

Same rear end ratios

I have noticed basically the same between my Dad's LLY and my LB7. I was surprised at the mileage difference. We both have the same tires, same ride height, both 4WD, etc. Really the only differences between our trucks is the color and mine has twice the miles on it.

imo I wouldn't do a thing, alot of expense for nothing. Alot of folks will tell you that the lb7 is better.....

I would not do it, but that is my opinion, the Lb7 being the first gen duramax and the LBZ is the third there are I am sur a lot of things that have been changed from year to year. Lb7 is a great motor, I would have one other than the money did not work out so I got a good deal on a LBZ. What is the reason that you are thinking of doing this?

i soon as well hope to be going back to a lb7 from my current lbz, your comments are what i am seeing as well, i was in the low 20mpgs and now trying to get to 20 with the lbz, then there is the cracked piston sydrome with the lbzs, sad thing to say the least