I just sold my lb7 and got an lly coming tomorrow and been hearing the mileage isn't as good in the lly's. any truth to this from you guys that have driven/owned both?? thanx

Welcome to the diesel emissions side.:cool: There isn't that much of a difference, but yes, the LB7 usually tops us on the miles per gallon part. Hopefully, in due time, the the Black Sheep will prevail and stand on top!

I have an 04.5 LLY cc/sb/4x4. A good riding buddy has a 04 LB7 cc/sb/4x4. When we go traveling, both pulling 7x14 enclosed cargo trailers, or running empty mileage is pretty much a wash between us. sometimes I'm better, sometimes he is better, but the difference is usually <0.5mpg hand calculated. Since our comparison is done traveling together, I'd say they are very comparable, certainly not a big difference at least in our comparison.

Another riding buddy has an 04LB7 ex/lb 4x4. We haven't traveled together in similar configurations, but comparing our mileage, again hand calculated empty again, numbers match pretty well, within 1mpg hiway empty.

that's what i like to hear. only 12 more hours till i pick it up.

I have owned 2 LB7's and 2 LLY's pretty much even.
USA-1

I had an '02 Ext cab 2500. Now I have an '05 cc 2500. The '02 was about 1 mpg better empty and 1.5-2 mpg better loaded. But the power of the '05 is much better IMO.

well, picked the truck up yesterday. sad to report that my lly doesn't get near the mileage my lb7 did. now, this is just based on my theory that i usually had in my lb7 around 2 hours of travel time at 110-120 km's/hour per 1/4 tank of fuel with the last 1/4 sucking down like my kids water in his bathtub. my lly seems to get around 1 1/2 hours to 1/4 tank which kind of blows. but seeing as how my mileage calculations are state of the art technology, i could be waaaay out in left field.lol this truck has a bully dog chip with 150 hp setting and a k&n air intake setup. my lb7 did not. just brain farting out loud, but wondering if the bully dog is screwing my mileage up compared to my juice attitude in my lb7. any thoughts, and keep your mocking to a minimum over my fuel calculations.

take her down to the #1 (50hp) tow economy setting and milage will come up. 150 hp setting is all about power without too much concern for milage. I have the same setup and just keep mine at tow/economy. Its still 50hp over stock.

My 05 LLY was a fuel pig, 13-15mpg unloaded at highway speeds.(75-80)
03 & 04 LB7's were better at 16-18mpg.
06 LLY has been the best one yet at a solid 18. For what it's worth.

I am hoping mine gets better as the miles increase. At 14k mine is getting around 15.3 mpg. Drops to 14.8 or so when pulling a 7000lb car trailer.

My 02 2500 HD 2WD got in the 20ish range when it is empty. My 05 3500 4X4 dually gets in the 17ish range when it is empty. I guess that the price you pay for a big butt. :)

kind of an odd thing, but i filled up with fuel at a certain station and it seems like my mileage improved immensly. I usually am not overly concerned with mileage, but this big of a drop kind of sucks. be very interesting to see if i continue to fill up at this station if my mileage gets better. also, when i was getting the crappy mileage, i was in the 2nd stage which i believe is 75 h.p. hope it gets better, talked to my buddy at dealership and he claimed the lbz's are getting worse mileage then the lly's. hope he's lying.

kind of an odd thing, but i filled up with fuel at a certain station and it seems like my mileage improved immensly. I usually am not overly concerned with mileage, but this big of a drop kind of sucks. be very interesting to see if i continue to fill up at this station if my mileage gets better. also, when i was getting the crappy mileage, i was in the 2nd stage which i believe is 75 h.p. hope it gets better, talked to my buddy at dealership and he claimed the lbz's are getting worse mileage then the lly's. hope he's lying.

My 05 LLY 2wd crew cab gets 21mpg highway "70ish mph" hand calculated "haven't calculated since I put on the new tires though"

my buddy has an 06 LBZ 4x4 ext. cab and he is only getting about 15mpg highway

My 05 LLY 2wd crew cab gets 21mpg highway "70ish mph" hand calculated "haven't calculated since I put on the new tires though"

my buddy has an 06 LBZ 4x4 ext. cab and he is only getting about 15mpg highway

consider yourself lucky. every guy i'm talking to is about as happy as i am with mileage on the lly. you wanna trade trucks.lol

Just completed 2900 mile run from FL to AZ and up to NE corner of NV carrying about 2000 lb. 18.5 mpg at cruise settings of 68 to 69 mph. Very little above 70 mph. Did a bit better last year. Maybe fuel quality.

Our LLY's get 19mpg or better <70mph highway unladen, long distance round trips. Blue got 17.5mpg when brand new from California to Florida at speeds of up to 95mph (stupid speed limiter). It got 15.x on the way back with a 8' tall CMM machine in the bed. Worst mileage is in the 10.x range towing heavy at high speed. City mileage is usually in the 14mpg range.

To be honest, that kind of mileage in a heavy pickup is remarkable.

guess i should actually calculate the mileage, it's prob alot better then i think. loving the truck though. gm does a bang up job on these trucks. 1/2 thought bout maybe a dodge or a ford, but then i kicked myself in the nads and woke up.:eek: keep up the great sight boyz.

On a 300 mile trip this weekend, I hit 18.1 hand calc and tire adjusted (unloaded).

I get a pretty consistent 13 mpg average in town. On a 300 mile trip to Dallas over Christmas I hit just over 20 mpg, but the elevation drops about 2000 feet. On the return trip I got 18. Overall highway unloaded it is usually in the 18 to 19 range. Towing 7K I get 13 in the winter and 11 in the summer with the AC and dang fan running. Can't gripe a whole lot my 95 C3500 CC with 454 got 6.5 towing the same trailer.

I get a pretty consistent 13 mpg average in town. On a 300 mile trip to Dallas over Christmas I hit just over 20 mpg, but the elevation drops about 2000 feet. On the return trip I got 18. Overall highway unloaded it is usually in the 18 to 19 range. Towing 7K I get 13 in the winter and 11 in the summer with the AC and dang fan running. Can't gripe a whole lot my 95 C3500 CC with 454 got 6.5 towing the same trailer.

My 98 3500 with the 454 got 6, of course those two extra injectors under the blower probably did that to me.

I tow with several other folks with similar loads, the Dodge HO and LLY are within a gallon of each other for fuel use in a typical weekend, about 100 gallons of fuel. That is 1%.. The beloved 7.3 powerstroke is always using more fuel, and he tows the smallest trailer of the bunch.

My '05 LLY with BFG at 265's gets 18-20MPG average, I don't take off fast which seems to make a big difference.

the one thing i'm noticing is if i drive this truck decent and not like i'm in nascar, the mileage is just as good as my lb7 as stated earlier. i've had a chance to test it out a little and come to this conclusion. the one thing i do notice is it seems to like the fuel a little more pulling trailers then the lb7(close, but it does take a little more petro for this) overall, the lly is winning me over. help me get fewer speeding tickets anyways by slowing down. :ro)